What is Mon Mod?

Mon Mod (Monster Modifier) is a web-based tool for creating, modifying, and scaling D&D 5th Edition monster stat blocks. Whether you need to tweak an existing monster to fit your encounter, build one from scratch, or scale a creature to a different Challenge Rating, this tool handles the math and formatting so you can focus on running your game.

Quick start

There are three main ways to begin:

• Create a blank monster: Click Create New in the toolbar, choose Blank Monster, and fill in the fields. The tool generates balanced stats based on the CR and role you select.
• Generate a random monster: Click Create New and choose Random Monster. You can optionally specify a creature type, role, and CR before generating a fully built creature in one click.
• Import an existing monster: Click Search to find a creature in the Open5e database, or use Import to bring in a stat block from JSON, Markdown, an image (OCR), or a PDF.

The two-panel layout

The interface is split into two main areas:

• Editor (left panel): Tabbed controls where you configure the monster's identity, abilities, adjustments, and more.
• Preview (right panel): A live stat block that updates instantly as you make changes. You can also click values directly in the preview to edit them inline.

Mobile and tablet support

The tool is fully responsive and works on phones and tablets. On small screens, tab buttons collapse into a dropdown menu, keeping the interface usable without a keyboard or mouse. The editor and preview panels split fluidly at 45%/55% rather than fixed pixel widths, and identity fields reflow at narrow widths. See the Mobile section for mobile-specific features like camera scan and help toasts.

The dark header bar at the top of the page contains a few key controls:

• Documentation link: Opens this documentation page.
• Theme button: Switches between visual themes for the stat block preview (parchment, dark, etc.).
• Sign In / Account menu: Create an account or log in to unlock cloud features. Once signed in, the menu includes Send a Note for sending feedback or suggestions directly to the developer.
• Support button (heart icon): Opens the Ko-fi donation page for supporting the project.

What signing in enables

Without an account, everything works locally in your browser. Signing in adds:

• Cloud save: Your monsters are saved to the cloud, not just your browser's local storage.
• My Monsters: A library of up to 10 saved monsters (or 100 for supporters), accessible from any device.
• My Abilities: Save up to 10 ability templates (or 100 for supporters) and reuse them across multiple monsters.
• My Spells: Save up to 10 spell templates (or 100 for supporters) for quick access.
• My Fields: Save up to 10 custom fields (or 100 for supporters) — creature types, damage types, conditions, languages, skills, and senses that persist across sessions.
• Account modal: Manage your profile, avatar, linked accounts, supporter status, and data from a central account panel.
• My Themes (supporter-only): Build and apply custom color themes for the stat block preview.
• Supporter badge: A gold ring appears around your avatar to indicate supporter status.
• Synced settings: Theme preferences sync to the cloud. Display settings such as format and background are stored locally in your browser.

The toolbar sits just below the header and gives you quick access to the most common actions.

Create New

Opens a panel over the editor (left side) with two options. No confirmation dialog is shown before replacing the current monster.

Options:

• Blank Monster: Starts with an empty stat block. You choose the CR, and the tool generates appropriate baseline stats using the current type and size from the Identity tab. Role is not available for Blank monsters.
• Random Monster: Generates a complete creature randomly. You can control the randomness with several options:
  • Type: Restrict to a specific creature type (e.g., Fiend, Undead) or leave it random.
  • Size: Pick a size or let it be chosen for you.
  • Role: Set a combat role (Brute, Controller, etc.) or randomize it. Sub-Role is always randomized automatically and is not user-selectable in this dialog.
  • CR variance: How far from the target CR the result may land. Useful for generating a monster that is "roughly CR 5."
  • Strict type matching: When enabled, only assigns abilities and traits that make thematic sense for the creature type.

Search

Opens a modal dialog for searching the Open5e monster database, which includes the SRD and community-contributed content. If you are signed in, your saved monsters also appear in search results. Type part of a name and select a result to load it into the editor. The modal closes automatically when you select a monster, or you can dismiss it with the X button, Escape, or by clicking the overlay.

By default, search results are deduplicated by name, keeping the preferred source (SRD/WotC takes priority). Uncheck the De-dupe checkbox next to the Filters button to see all versions of a monster from every source.

Import

Lets you bring in a stat block from an outside source. Supported formats:

• JSON: Paste Open5e-format JSON directly.
• Markdown: Paste a Markdown-formatted stat block (e.g., from Homebrewery or GM Binder).
• Image / OCR: Upload a photo or screenshot of a stat block. The tool opens an interactive crop modal where you draw a selection box around the stat block, then uses optical character recognition to extract the text and convert it.
• Scan (mobile only): A Scan button appears next to Import on iOS and Android. Tapping it opens the device camera so you can photograph a stat block directly. The image goes through the same crop and OCR pipeline as a standard image import.
• PDF: Upload a PDF containing a stat block.

OCR works best with clean, high-contrast images. A cropped screenshot of a single stat block gives much better results than a photo of a full page.

When an import fails, an anonymous error report is sent automatically to help diagnose issues. See the Privacy & Telemetry section for details.

Help Box

Hover over (or focus) any control in the editor to see a brief explanation of what it does in the help box area. This contextual help is especially useful when you encounter unfamiliar options like scaling modes or CR variance.

The editor panel is organized into five tabs. Each tab groups related settings together so you can work on one aspect of a monster at a time.

4a. Identity Tab

This is where you define who and what the monster is: its name, type, size, scores, and the many small details that appear in the top portion of a stat block.

Basic Info

• Name: The creature's display name.
• Challenge Rating (CR): A stepper control that sets the monster's intended difficulty. Supported values are 0, 1/8, 1/4, 1/2, and 1 through 30. The CR drives baseline stat generation: higher CR means more HP, higher attack bonuses, and so on.
• Initiative tiers: Choose how the monster's initiative is determined. This is a 2024 Monster Manual convention. The control cycles through three states: None (no initiative bonus), Proficiency (adds the proficiency bonus), and Expertise (adds double the proficiency bonus).

Type, Subtype, Size, Alignment

Standard dropdowns with all official options, plus the ability to type in custom entries. If your monster is a "Symbiotic Ooze" or "Chaotic Adorable," go for it. The alignment dropdown includes all 9 "Typically X" variants used in the 2024 Monster Manual format, in addition to the standard alignments and "Any X" options.

Subtype: A text field that appears between Type and Size for the parenthetical subtype shown in the stat block's meta line (e.g., "humanoid (any race)" or "fiend (demon)"). Leave it blank to omit the parentheses entirely.

Habitat: A free-text field for the creature's typical environment (e.g., Forest, Underdark, Arctic). Included in exports.

Role & Sub-Role

Roles shape how the tool distributes stats when creating a monster from scratch. A Brute gets more HP and melee damage, a Skirmisher favors speed and Dexterity, and so on. Sub-roles add a secondary emphasis. These are purely for generation; they do not appear in the final stat block.

Spellcasting Ability

Sets which ability score governs the monster's spellcasting (Wisdom, Charisma, Intelligence, etc.). This affects spell save DC and spell attack bonus in the stat block.

Ability Scores

The six classic scores (STR, DEX, CON, INT, WIS, CHA). When you create a new monster, these are auto-generated from the CR and role to give you a balanced starting point. You can freely edit any score afterward.

Speed

Five movement types are available: Walk, Fly, Swim, Climb, and Burrow. Each has its own field. Set any you do not need to 0 or leave it blank.

Senses

A multi-select control with range steppers for each sense (Darkvision, Blindsight, Tremorsense, Truesight). You can also add custom sense entries. Passive Perception is calculated automatically from the monster's Wisdom and proficiency.

Languages

Multi-select with all standard D&D languages. Two special toggles:

• "No languages": The creature has no languages at all (typical for beasts and some monstrosities).
• "Can't speak": The creature understands languages but cannot speak them. Adds "understands X but can't speak" to the stat block.

Telepathy is available as a language option with a configurable range (default 120 ft.). Custom language entries are supported for homebrew settings.

Save & Skill Proficiencies

Toggle which saving throws and skills the monster is proficient in. Bonuses are calculated automatically from ability scores and proficiency bonus (determined by CR).

Damage Vulnerabilities, Resistances, Immunities & Condition Immunities

Multi-select lists for damage vulnerabilities, damage resistances, damage immunities, and condition immunities. These support custom entries through the My Fields feature. The damage type lists include grouped physical damage options: "Bludgeoning, Piercing, and Slashing" with variants for nonmagical attacks, non-silvered attacks, and non-adamantine attacks, in addition to the individual damage types. Vulnerabilities follow the same format and appear before resistances in the stat block.

Notable Loot

A free-text field for treasure or items the creature carries. This appears at the bottom of the stat block and is handy for DMs who want loot info right on the stat block.

4b. Abilities Tab

This tab is where you build the monster's actions, traits, reactions, and special abilities: everything that makes it interesting in combat.

Adding abilities

Click Add Ability in the Abilities toolbar to create a new blank ability. It starts as a freeform text block; you can then set its type to change what fields are available.

The toolbar also contains a Use Template button. Clicking it opens the Browse Abilities modal and adds a new ability pre-filled from the selected template. This always creates a new ability and does not overwrite any existing ability.

Browse Abilities

Click Use Template (or the Browse Abilities shortcut) to open a modal dialog for finding and applying pre-built abilities. The modal uses a tabbed interface with the following tabs: Traits, Actions, Bonus Actions, Reactions, Legendary, and Spells. Each tab contains sub-headers for granular browsing within that category.

• Feature catalog entries: Entries that affect CR calculation display an "Affects CR" badge. Applying one of these entries links it to the CR system, so its contribution is included in the CR diagnostic.
• CR-linked editing: After applying a catalog feature, you can edit its text freely without breaking the CR link. The mechanical values remain connected to the CR calculation even if you adjust the description.
• Search: A search bar filters results within the active tab, making it easy to find specific abilities by name or keyword.
• My Abilities: Your saved custom ability templates (requires sign-in) are available within the relevant tabs.
• Spell templates: The Spells tab lets you search the Open5e spell database and add spells directly. My Spells (requires sign-in) appear here as well.

Ability types

• Attack: Melee or ranged weapon attacks, or spell attacks. Generates the standard "to hit" line with damage.
• Save: Abilities that force targets to make a saving throw (area effects or single-target).
• Spell: A named spell with level, frequency, shorthand display, and optional save information. The four frequency options are At Will, 3/Day, 2/Day, and 1/Day. Slot-based spellcasting is controlled by the display format (2014 Slot Caster), not by per-spell frequency.
• Freeform: Plain descriptive text with no mechanical fields. Use this for traits, lore, or anything that does not fit the other types.

Section

The Section dropdown determines which section of the stat block the ability appears in. Changing this dropdown moves the ability to the selected section. Available sections are: Traits, Actions, Bonus Actions, Reactions, Legendary Actions, Mythic Actions, and Lair Actions.

Usage / Recharge

The Usage field sets how often the ability can be used. Options are: At Will, Recharge 5-6, Recharge 6, X/Day, X/Short Rest, and X/Long Rest. When an X/Day variant is selected, a count input appears to specify the number of uses. This field is hidden for the Spell type, which uses the Frequency field instead.

Attack configuration

When an ability is set to Attack type, you configure:

• Attack type: Melee Weapon, Ranged Weapon, Melee or Ranged Weapon, Melee Spell, or Ranged Spell.
• Reach / Range: How far the attack extends (5 ft. reach, 120 ft. range, etc.).
• Targets: How many targets the attack can hit.
• Notes: A free-text field for extra qualifying text such as "with disadvantage" or "against a grappled target." By default the note is inserted after the to-hit line. Check After targets to place it after the target description instead.

Save configuration

When an ability is set to Save type, you configure:

• Saving throw ability: Which ability score the target rolls against (DEX, CON, WIS, etc.).
• Effect: What happens on a failure.
• Area shape and size: If the ability affects an area.

Area options

Several area shapes are available, each with relevant sub-fields:

• Target(s): Affects one or more specific targets. Configure count and range.
• Radius (from self): An emanation centered on the creature.
• Cone: A cone-shaped area originating from the creature.
• Line: A straight line from the creature.
• Sphere: A spherical area at a point within range.
• Cube: A cubic area at a point within range.
• Cylinder: A cylindrical area at a point within range.

Special checkboxes

• Must be visible: Adds "that [monster name] can see" to the targeting text. Useful for gaze attacks and similar abilities.
• Exclude self: For area effects, ensures the monster is not affected by its own ability.

Damage entries

Each ability can have one or more damage entries. For each entry, you set:

• Dice / flat amount: The damage dice (e.g., 2d6) or a flat number.
• Damage type: Slashing, Fire, Necrotic, Healing (used for abilities that restore hit points), etc.
• Ability modifier: Whether to add an ability modifier to the damage.
• "Scales with CR" checkbox: When enabled, this damage automatically adjusts when you change the monster's CR. This is how you make damage keep pace with CR without manually recalculating dice. See the Scaling & CR section for details.

Riders

Riders are additional effects that trigger on a hit or failed save. Each rider is organized into five labeled rows:

• Effect row: The condition applied to the target (Grappled, Poisoned, Restrained, etc.), with a duration field and an optional "Affects" qualifier (e.g., affects only certain targets).
• Save row: A saving throw the target can make to resist or end the condition, including the save ability (STR, CON, DEX, etc.) and a "Half on save" checkbox for partial-effect abilities. For save-to-end riders, a timing option lets you choose whether the save occurs at the start or end of the target's turn.
• Damage row: Extra dice damage tied to the rider, with a damage type and an optional "Scales with CR" checkbox so the bonus damage adjusts when the monster is rescaled. When "Scales with CR" is checked, rider damage scales alongside the monster's CR just like primary damage entries.
• Movement row: A forced movement effect. Options are Push, Pull, Teleport, and Free Move, each with a distance field. Free Move also has a "No opportunity attacks" checkbox to indicate the movement does not provoke.
• Extra row: A freeform text field for any effect that does not fit the other rows, plus a remove button to delete the rider.

Description preview

As you configure an ability, the tool auto-generates the stat block text in real time. You can see exactly what the final wording will look like. If the auto-generated text is not quite right, you can edit the description directly with a text override. A reset button restores the auto-generated version. For freeform abilities there is nothing to generate from, so the reset button does not appear.

Saving abilities for reuse

Click the save icon on any ability to store it in My Abilities or My Spells (depending on type). Saved abilities can be loaded into any future monster via the template picker.

Managing abilities

• Duplicate: Creates a copy of the ability. Great for making a stronger or weaker variant.
• Delete: Removes the ability. Requires three clicks as a safety measure to prevent accidental deletion.
• Enable / Disable: Temporarily hides an ability from the stat block without deleting it.
• Drag to reorder: Grab the drag handle to move abilities up or down in the list.
• Change section: Use the Section dropdown on an ability to move it to a different section of the stat block (Traits, Actions, Bonus Actions, Reactions, Legendary Actions, Mythic Actions, or Lair Actions).

Special features

• Multiattack: Configure a Multiattack action that combines multiple attacks into one action. The tool generates the standard Multiattack text based on which attacks you include.
• Legendary Actions: Enable legendary actions and set how many the monster gets per round (the total action budget). Individual abilities can be assigned to the Legendary Actions section using the Section dropdown.
• Legendary Resistance: Add the classic "X/Day" legendary resistance feature.
• Mythic: Enable mythic traits and actions for two-phase boss monsters.
• Lair: Add lair actions and regional effects.

Unified Ability Catalog

The Browse Abilities modal includes a built-in catalog of 129 feature entries, all browsable through the tabbed interface. These structured presets go beyond simple text templates and include mechanically complete abilities such as:

• Charge attacks: Abilities that deal bonus damage or knock targets prone when the creature moves before attacking.
• Trigger-based abilities: Reactions and traits that activate on specific triggers, such as on-death explosions or retaliatory strikes.
• Weapon attacks with riders: Attacks that include built-in grapple, restrain, or other conditions, with escape alternatives (such as escape DCs or Strength checks) already configured.

Catalog entries that affect CR calculation are marked with an "Affects CR" badge. When you apply one of these entries, the tool links it to the CR system automatically. This means the ability's mechanical contribution (damage, save DC, conditions) is factored into the CR diagnostic without any extra setup.

4c. Adjustments Tab

The Adjustments tab lets you fine-tune a monster's stats without editing individual fields. This is especially useful when you want to make a monster tougher or weaker without rebuilding it from scratch.

Flat stat adjustments

Add or subtract flat amounts from:

• Hit Points (HP)
• Armor Class (AC)
• Attack bonus (ATK)
• Save DC
• Spell DC
• Speeds (all movement types)

Ability score adjustments

Add or subtract from individual ability scores (STR, DEX, CON, INT, WIS, CHA). Downstream values like save bonuses and skill checks update automatically.

Ratio adjustments

• HP ratio: Multiply HP by a percentage. Useful for making a creature 50% tougher (1.5x) or a glass cannon (0.5x).
• DPR ratio: Multiply damage per round by a percentage. Affects all damage entries marked as "Scales with CR."

CR settings

• Target CR: The CR you want the monster's stats to target.
• Benchmark edition: Whether to use 2024 or 2014 stat benchmarks for CR calculation. The two editions have different expectations for HP, AC, and damage at each CR.
• CR variance: How strictly the stats must match the CR target. A loose variance lets the monster deviate from the benchmark without the tool flagging it.

CR Diagnostic

A visual breakdown showing how the tool calculates the monster's CR. It displays:

• Defensive CR (based on HP and AC)
• Offensive CR (based on damage per round and attack bonus / save DC)
• The final CR as the average of defensive and offensive

Check the CR Diagnostic after making significant changes. It helps you understand whether your monster is over- or under-tuned relative to its CR.

4d. Source Tab

The Source tab appears for imported monsters and gives you low-level control over the raw data.

• JSON editor: Paste or edit the raw JSON data that defines the monster.
• Load Monster button: Parses the JSON and loads it into the editor.
• Source Edition: Whether the original stat block was written for the 2024 or 2014 rules.
• Output Edition: Controls which edition's benchmarks the stats are scaled toward. Located next to Source Edition in Import Settings, this is separate from the Display Format (which controls visual appearance only). Use this to convert monsters between 2014 and 2024 editions. For example, you can import a 2014 monster and scale its stats to 2024 benchmarks while keeping whichever display format you prefer.
• Scaling Mode:
  • Input: Preserves the original stat ratios and scales them proportionally.
  • Benchmark: Fits the stats to the standard benchmark values for the target CR.
• Source CR override: If the tool detected the wrong CR from the import, you can correct it here.

Imported Bonuses

When you import a monster, the tool compares each skill bonus, save bonus, and initiative bonus against what standard calculation (ability modifier + proficiency bonus) would produce. If a value differs from the standard, the tool records the difference as a delta and displays it in the Imported Bonuses section.

For example, if an imported monster has Perception +10 but standard calculation gives +1 (WIS modifier -1, plus proficiency bonus +2), the tool records a delta of +9. This delta is preserved when you scale the monster to a different CR: the standard portion (ability mod + PB) adjusts naturally, while the +9 custom bonus carries forward.

• Input scaling mode: Deltas are applied. The monster's bonuses match the imported values at its original CR, and scale proportionally when the CR changes.
• Benchmark scaling mode: Deltas are ignored. The tool uses pure standard calculation, fitting everything to CR benchmarks. Switching back to Input mode re-applies the deltas.

Each delta row has an editable value and a remove button. You can:

• Edit a delta to correct import errors (e.g., a stat block with a typo).
• Remove a delta to drop an individual custom bonus.
• Add a new delta using the "Add bonus..." dropdown to manually assign a custom bonus to any skill, save, or initiative.
• Clear All to remove every delta at once, reverting to standard calculation.

Changed values flash in the preview stat block when you edit deltas, just as they do with any other modification.

4e. Compare Tab

The Compare tab lets you view two stat blocks side by side. This is invaluable for verifying that your modifications have not accidentally broken something, or for comparing your custom monster against an official one.

• Capture: Snapshots the current stat block so you can continue editing and see changes relative to the captured version.
• Search Monsters: Opens a modal dialog to find and load a different monster for comparison. Works the same as the toolbar Search: dismiss with X, Escape, or overlay click.
• Edit / Copy / Clear: Modify the captured snapshot, copy it, or clear it to start over.
• Zoom: When a compare monster is loaded, zoom controls appear to zoom in/out on the compare preview. Click the percentage label to reset to fit-to-width.

The right side of the screen shows a live stat block that updates instantly as you make changes. It is not just a preview; it is also an interactive editor.

Interactive editing

Click on most values directly in the stat block to edit them inline:

• Click the AC value to open a popover with both the AC number and a Source field for the armor description (e.g., "natural armor," "breastplate"). Leave Source blank to omit the parenthetical.
• Click the initiative value to open a popover and set the proficiency tier: None (no bonus), Proficiency (adds proficiency bonus), or Expertise (adds double proficiency bonus).
• Click the Size, Type, or Alignment portions of the meta line to open a popover for that specific field. The Type popover also includes a Subtype text input for the parenthetical qualifier.
• Click HP to adjust hit points or the hit dice formula.
• Click damage values in abilities to change dice or amounts.
• Click save DCs to adjust difficulty.
• Click conditions and other text to edit them.
• Click an individual skill bonus to open a popover with a Remove button.
• Click an individual sense to open a popover with a range input and a Remove button.
• Click an individual language to open a Remove popover.
• Click the Skills, Senses, or Languages label to navigate directly to the Identity tab.

Drag abilities

Grab an ability's name in the stat block to drag it to a new position. This reorders the ability within its section (Traits, Actions, Bonus Actions, Reactions, etc.).

Hover controls

When you hover over sections in the stat block, additional controls appear:

• × button: Remove an ability from the stat block.
• + button: Add a new ability to that section.

Resize handle

A drag handle on the right edge of the stat block lets you resize its render width. Drag it left or right to make the stat block narrower or wider. The default render width is 800px. You can also adjust the width using the +/- buttons in the sheet controls.

Zoom-to-fit scaling

The stat block always renders at its full intended width regardless of viewport size. When the preview area is narrower than the render width, the stat block is scaled down proportionally so it fits without horizontal scrolling. Use the Zoom controls in the sheet controls to zoom in or out. Click the zoom percentage to reset to fit-to-width. Exports (PNG/PDF) always capture at the full render width, not the zoomed size.

Sheet controls

Above the stat block, you will find display options:

• Sheet Theme: Change the visual appearance of the stat block.
• Format: Switch between 2024 and 2014 stat block layouts.
• Image: Two controls for the creature image: a checkbox to show or hide the image, and a separate upload button to set the image file. When visible, the image can be dragged to reposition it above, beside, or below the AC/HP/Speed block. Corner handles resize it, and the center handle pans the visible portion. On touch devices, tap the image to reveal the handles.
• Background: A three-option selector: Texture (parchment background), Solid (flat color, with a color picker to choose the color), or Transparent (no background).
• Single-Column: Force a single-column layout (useful for narrow displays or export).
• Notes: Add DM notes that appear below the stat block.
• Width: Set the stat block render width in pixels (default 800). Use the +/- buttons or type a value directly.
• Zoom: Zoom in or out on the preview. Click the percentage label to reset to fit-to-width.

On mobile, these controls are hidden behind a Settings button to save space. Tap it to expand/collapse the controls.

Export options

Export your finished stat block in several formats:

• JSON: Open5e format, 5eTools Homebrew format, or Improved Initiative format.
• Markdown: Standard Markdown or Homebrewery Markdown, for use in text-based tools, VTTs, or note-taking apps.
• XML: Fight Club 5e format for the Fight Club app.
• Image: Export as PNG or PDF. Great for printing or sharing on social media.

Mythic actions are included in all export formats (JSON, Markdown, XML, Improved Initiative). When the Notes toggle is enabled in Sheet Controls, DM notes are included in JSON, Markdown, and XML exports.

Creating a free account unlocks cloud storage and sync features. Without an account, everything is stored in your browser's local storage and will be lost if you clear your browser data.

My Monsters

Save up to 10 monsters to the cloud (or 100 with supporter status). These are accessible from any device where you sign in. Additionally, your most recent monsters are cached in local storage for quick access. You can export multiple saved monsters as a single JSON file for backup or sharing, and import monsters from a JSON file into your library.

My Abilities

Save ability templates (attacks, traits, reactions) for reuse across multiple monsters. Free accounts can save up to 10 abilities, while supporters can save up to 100. If you have built the perfect Breath Weapon or a custom trait you use for all your homebrew dragons, save it once and load it into any future creation.

My Spells

Save spell templates for reuse. Free accounts can save up to 10 spells, and supporters can save up to 100. Useful if you have custom or modified spells that are not in the Open5e database.

My Fields

Extend the tool's built-in lists with your own custom entries. Free accounts can save up to 10 custom fields, while supporters can save up to 100.

• Custom creature types
• Custom damage types (e.g., "Psychic Fire" or "Void")
• Custom conditions
• Custom languages
• Custom skills
• Custom senses

These custom fields appear in the relevant dropdowns and multi-selects throughout the editor, making them as easy to use as the built-in options.

Send a Note

Available from the account menu when signed in. Use this to send feedback, bug reports, or feature suggestions directly to the developer. Messages are delivered privately and do not require an external email client.

Account Modal

The account modal provides a central hub for managing your profile and data. It includes:

• Profile: Set your display name and avatar. You can upload a custom image or choose from a library of creature icons.
• Linked accounts: View and manage sign-in providers linked to your account.
• Supporter status: See whether you have active supporter benefits and view your donation history.
• Storage usage: A breakdown of how many monsters, abilities, spells, and fields you have saved relative to your limits.
• Data export/import: Export all your saved data as a backup file, or import data from a previous export.
• Privacy: Opt in to enhanced telemetry (browser info and user-created text included in error reports). This is off by default. See the Privacy & Telemetry section.
• Clear data: Remove all saved content from your account while keeping the account itself.
• Delete account: Permanently delete your account and all associated data.

Supporter Benefits

Monster Modifier is free to use. Donations through Ko-fi help support ongoing development. Each $1 donated grants one month of supporter status, and recurring donations keep the benefits active continuously.

Supporter benefits include:

• No ads across the tool (non-supporters see a sticky ad banner at the bottom of the screen on mobile, and an in-panel ad on desktop)
• Increased storage limits: 100 monsters, 100 abilities, 100 spells, and 100 custom fields (up from 10 each)
• Access to My Themes for building custom color themes
• A gold supporter badge displayed around your avatar
• Feelings of joy and satisfaction

My Themes

A supporter-only feature for creating custom color themes for the stat block preview. Build your own theme by choosing colors for backgrounds, text, borders, accents, and other visual elements. Custom themes appear alongside the built-in options in the theme picker and are synced to your account.

How it works

The tool automatically takes a snapshot of the entire monster state every time you make a change. This means you can freely experiment knowing that every previous state is recoverable.

Keyboard shortcuts

• Ctrl+Z (or Cmd+Z on Mac): Undo the last change.
• Ctrl+Shift+Z (or Cmd+Shift+Z): Redo.

Coalescing

When you make rapid changes in quick succession (e.g., typing a name letter by letter, or clicking a stepper multiple times), the tool groups them into a single undo step. This means pressing undo will not step back one character at a time; it will jump back to the state before you started typing.

How CR calculation works

Challenge Rating is calculated by averaging two components:

• Defensive CR: Determined by the creature's Hit Points and Armor Class. More HP and higher AC push the defensive CR up.
• Offensive CR: Determined by the creature's Damage Per Round (DPR) and its attack bonus or save DC. More damage and higher accuracy push the offensive CR up.

The final CR is the average of these two. This follows the guidelines in the Dungeon Master's Guide.

Benchmark editions

The 2024 and 2014 Dungeon Master's Guides have different benchmark tables for what stats a monster should have at each CR. For example, the 2024 benchmarks generally expect higher HP at high CRs than the 2014 tables.

Choose the edition that matches the style of game you are running. If you use the 2024 Monster Manual monsters as your baseline, choose 2024 benchmarks.

Scaling modes

• Benchmark mode: Fits the monster's stats to the standard benchmark values for the target CR. An imported CR 5 monster scaled to CR 10 will get the HP, AC, damage, and attack bonus that the benchmark table says a CR 10 creature should have.
• Input mode: Preserves the original stat ratios and scales proportionally. If the original monster had unusually high HP but low AC for its CR, the scaled version will maintain that same ratio at the new CR. This is useful for keeping a monster's "feel" intact while adjusting its power level. Input mode also preserves imported bonus deltas for skills, saves, and initiative.

How "Scales with CR" works

When you check the "Scales with CR" box on a damage entry, that damage will automatically adjust when you change the monster's target CR. The tool recalculates the dice to match the expected DPR for the new CR, spreading the damage across all scaling entries proportionally.

Damage entries without this checkbox are treated as fixed: they stay the same regardless of CR changes.

Mark your monster's primary attacks as "Scales with CR" and leave situational or low-impact damage as fixed. Rider damage can also scale with CR when its own "Scales with CR" checkbox is checked, which is useful for riders that should grow alongside the monster's power level.

Cross-edition conversion

The Output Edition setting in the Source tab lets you convert monsters between the 2014 and 2024 rules. Set the Source Edition to match the original stat block, then set the Output Edition to the target edition. The tool scales the monster's stats toward the benchmarks of the output edition while preserving the creature's relative strengths and weaknesses. This is separate from the Display Format, which only controls the visual presentation of the stat block.

Source CR vs Target CR

Source CR is the CR the monster was originally designed for (detected from import or set manually). Target CR is the CR you want the monster to be. The difference between these two drives how much the stats are adjusted during scaling.

The tool supports three stat block format options, matching the evolution of D&D 5th Edition's presentation style:

2024 Format

The current Monster Manual style introduced in the 2024 revision. Spells are listed inline as individual actions or traits with frequency tags (e.g., "3/Day: Fireball"). This format is streamlined and easier to run at the table because each spell is self-contained.

2014 Slot Caster

The classic Player's Handbook spellcasting format. Spells are grouped by level with a number of spell slots per level (e.g., "1st level (4 slots): shield, magic missile"). This is the traditional format from the original 2014 Monster Manual, used for monsters that cast spells the same way PCs do.

2014 Innate Caster

The innate spellcasting format from the 2014 rules. Spells are grouped by frequency (At will, 3/day each, 1/day each) without spell slots. Used for creatures with natural magical abilities rather than learned spellcasting.

How format affects spell display

Switching formats changes how the same spells are presented in the stat block. The spells themselves do not change; only the formatting does. This makes it easy to convert a 2014-style monster to the 2024 presentation (or vice versa) with a single click.

Shortcut	Action
Ctrl+Z / Cmd+Z	Undo
Ctrl+Shift+Z / Cmd+Shift+Z	Redo
Ctrl+Y	Redo (alternative)
Escape	Close modals, popovers, and overlays
↑ ↓ in CR inputs	Increment / decrement CR value

Start with a template, then customize

Rather than building every ability from scratch, search the Open5e database for a similar monster and modify it. This gives you a solid baseline and saves time on common abilities like Multiattack, bite attacks, and breath weapons.

Use roles for balanced stat generation

When creating a new monster, always set a role (Brute, Skirmisher, Controller, etc.). Roles distribute ability scores and stats in a way that creates a coherent combat identity. A Brute with high STR and CON "feels" different from a Controller with high INT and WIS, even at the same CR.

Check the CR Diagnostic after making changes

The CR Diagnostic in the Adjustments tab shows you exactly how the tool is calculating your monster's CR. After adding abilities or changing stats, glance at it to make sure your monster lands where you intend. If the offensive CR is much higher than the defensive CR, your monster is a glass cannon, dangerous but fragile.

Use "Scales with CR" on damage you want to auto-adjust

If you plan to rescale your monster to different CRs, mark the main damage sources (primary attacks, breath weapons, etc.) with "Scales with CR." Leave minor or thematic damage (poison riders, environmental effects) as fixed. This keeps scaling clean and predictable.

Save custom abilities and spells for reuse

If you have homebrewed a signature ability (like a custom breath weapon or a unique reaction), save it to My Abilities. Next time you build a monster, it is one click away instead of a rebuild from memory.

Use Compare to verify changes against the original

Before committing to your modifications, use the Compare tab to capture the original stat block. Then make your changes and compare side by side. This is especially useful when scaling a monster to a new CR, so you can see exactly what changed.

Responsive layout

The editor and preview panels use a fluid 45%/55% split rather than fixed pixel widths. Below 1024px, the tab buttons are replaced by a dropdown selector. At very narrow widths, identity fields reflow into additional rows so nothing gets clipped.

The Adjustments tab label shortens to "Adjust" at narrow widths to fit the available space.

Camera scan

On iOS and Android, a Scan button appears next to Import in the toolbar. Tapping it opens the device camera so you can photograph a printed or displayed stat block. The captured image goes through the same interactive crop and OCR pipeline as a standard image import.

Help toasts

On touch devices, the desktop help box is replaced by contextual help toasts:

• Tap a field label to see a short description of what that field does, shown as a toast at the bottom of the screen.
• Tap and hold a control to read its help text without activating the control. The toast stays visible while you hold, plus 3 seconds after you release.

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Automatic error reporting

When an import, pipeline, or export error occurs, an anonymous error report is sent automatically to help diagnose and fix issues. These reports contain only technical data: the imported monster data (from public sources), parse flags, error messages, and the build version. No personal information is included by default.

Enhanced telemetry (opt-in)

You can optionally help further by enabling enhanced telemetry in Account > Privacy. When enabled, error reports also include your browser and device information and any user-created ability text associated with the error. This setting is opt-in and can be changed at any time.

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