— Design & Creative

Free 5e Stat Block Previewer

Paste a monster stat block to see it laid out, export it, and check that its numbers add up.

— Samples
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What is a 5e Stat Block Previewer?

This stat block previewer lays out fifth-edition monster stat blocks and checks their math. Paste a block written in the plain SRD style, in Homebrewery Markdown or in the 2024 layout, and see it formatted, converted to tidy Markdown or JSON, and recalculated line by line.

Every number that follows from another is worked out again: ability modifiers, average hit points and the hit die for the creature’s size, XP and proficiency bonus for its challenge rating, saving throws, skills, attack bonuses, average damage and passive Perception. Mismatches are listed with the value they should have.

Key Features

Three Layouts

Plain SRD style, Homebrewery Markdown and the 2024 layout.

Math Check

Modifiers, hit points, XP, saves, attacks and damage recalculated.

Formatted Block

The classic two-column look, with section headings.

Markdown and JSON

Export a tidy block for documents or tools.

Size and Hit Dice

Flags hit dice that don’t match the creature’s size.

Perfect for everyone

  • Game masters
  • Homebrew designers
  • Adventure writers and anyone converting monsters

How to Use the 5e Stat Block Previewer

Paste a stat block copied from your notes, a homebrew document or a PDF, or open a Markdown file. The formatted block, exports and checks update as you type, so a corrected number disappears from the problem list straight away.

1

Paste the Block

Name first, then the usual lines, in any of the three layouts.

2

Read the Layout

Check every field landed in the right place.

3

Run the Check

Fix numbers that don’t follow from the rest.

4

Export

Copy Markdown or JSON for your documents or tools.

Worked Examples

Stat Blocks, Rechecked

Each row is a stat block of the kind homebrewers write, with original creatures and a few deliberate mistakes. Each answer is this tool’s check, Markdown or JSON, with every derived number worked out again from the rules arithmetic.

REF_001An original construct, every number checked

“Clockwork Hound Medium Construct, Unaligned Armor Class 14 (natural armor) Hit Points 33 (6d8 + 6) Speed 40 ft. STR 15 (+2) DEX 14 (+2) CON 12 (+1) INT 3 (-4) WIS 12 (+1) CHA 1 (-5) Skills Perception +3 Damage Immunities poison, psychic Condition Immunities charmed, exhaustion, frightened, poisoned Senses darkvision 60 ft., passive Perception 13 Languages understands the languages of its creator but can't speak Challenge 1 (200 XP) Keen Smell. The hound has advantage on Wisdom (Perception) checks that rely on smell. Actions Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4 + 2) piercing damage.”

REF_002A Homebrewery block tidied into Markdown

“___ > ## Ember Drake >*Large Dragon, Chaotic Neutral* > ___ > - **Armor Class** 16 (natural armor) > - **Hit Points** 75 (10d10 + 20) > - **Speed** 40 ft., fly 60 ft. >___ >|STR|DEX|CON|INT|WIS|CHA| >|:---:|:---:|:---:|:---:|:---:|:---:| >|18 (+4)|12 (+1)|15 (+2)|8 (-1)|11 (+0)|10 (+0)| >___ > - **Saving Throws** Dex +4, Con +5 > - **Damage Immunities** fire > - **Senses** darkvision 60 ft., passive Perception 10 > - **Languages** Draconic > - **Challenge** 5 (1,800 XP) > ___ > ### Actions > ***Bite.*** *Melee Weapon Attack:* +7 to hit, reach 10 ft., one target. *Hit:* 15 (2d10 + 4) piercing damage. > ***Fire Breath (Recharge 5–6).*** The drake exhales fire in a 30-foot cone. Each creature in that area must make a DC 13 Dexterity saving throw, taking 31 (7d8) fire damage on a failed save, or half as much on a success.”

REF_003A 2024-layout creature, checked

“Bog Lantern Sprite Tiny Fey, Neutral AC 13 Initiative +3 (13) HP 10 (4d4) Speed 10 ft., fly 40 ft. STR 3 -4 -4 DEX 16 +3 +3 CON 10 +0 +0 INT 12 +1 +1 WIS 12 +1 +1 CHA 14 +2 +2 Skills Stealth +7 Senses Darkvision 60 ft.; Passive Perception 11 Languages Sylvan CR 1/2 (XP 100; PB +2) Traits Lantern Glow. The sprite sheds dim light in a 10-foot radius. Actions Spark. Ranged Attack Roll: +5, range 60 ft. Hit: 6 (2d4 + 1) Lightning damage.”

REF_004The same hound after four careless edits

“Clockwork Hound Medium Construct, Unaligned Armor Class 14 (natural armor) Hit Points 35 (6d8 + 6) Speed 40 ft. STR 15 (+2) DEX 14 (+2) CON 12 (+1) INT 3 (-4) WIS 12 (+1) CHA 1 (-5) Skills Perception +3 Damage Immunities poison, psychic Condition Immunities charmed, exhaustion, frightened, poisoned Senses darkvision 60 ft., passive Perception 11 Languages understands the languages of its creator but can't speak Challenge 1 (100 XP) Keen Smell. The hound has advantage on Wisdom (Perception) checks that rely on smell. Actions Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (2d4 + 2) piercing damage.”

REF_005Expertise on a skill

“Alley Cutpurse Small Humanoid, Chaotic Neutral Armor Class 13 Hit Points 9 (2d6 + 2) Speed 30 ft. STR 8 (-1) DEX 14 (+2) CON 12 (+1) INT 11 (+0) WIS 10 (+0) CHA 12 (+1) Skills Sleight of Hand +6, Stealth +4 Senses passive Perception 10 Languages Common Challenge 1/8 (25 XP) Actions Dagger. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage.”

REF_006A Large creature rolled with Medium dice

“Marsh Brute Large Giant, Chaotic Evil Armor Class 11 (hide armor) Hit Points 27 (6d8) Speed 40 ft. STR 19 (+4) DEX 8 (-1) CON 10 (+0) INT 5 (-3) WIS 7 (-2) CHA 7 (-2) Senses darkvision 60 ft., passive Perception 8 Languages Giant Challenge 2 (450 XP) Actions Club. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.”

REF_007A spellcaster’s saves and spell attack

“Hedge Mage Medium Humanoid, Neutral Armor Class 12 Hit Points 22 (5d8) Speed 30 ft. STR 9 (-1) DEX 14 (+2) CON 10 (+0) INT 16 (+3) WIS 12 (+1) CHA 10 (+0) Saving Throws Int +5, Wis +4 Senses passive Perception 11 Languages Common, Elvish Challenge 2 (450 XP) Actions Arcane Bolt. Ranged Spell Attack: +5 to hit, range 120 ft., one target. Hit: 10 (3d6) force damage.”

REF_008A tiny creature with the wrong XP

“Cellar Rat Tiny Beast, Unaligned Armor Class 10 Hit Points 1 (1d4 - 1) Speed 20 ft. STR 2 (-4) DEX 11 (+0) CON 9 (-1) INT 2 (-4) WIS 10 (+0) CHA 4 (-3) Senses darkvision 30 ft., passive Perception 10 Challenge 1/8 (50 XP) Actions Bite. Melee Weapon Attack: +0 to hit, reach 5 ft., one target. Hit: 1 piercing damage.”

REF_009The spellcaster as JSON

“Hedge Mage Medium Humanoid, Neutral Armor Class 12 Hit Points 22 (5d8) Speed 30 ft. STR 9 (-1) DEX 14 (+2) CON 10 (+0) INT 16 (+3) WIS 12 (+1) CHA 10 (+0) Saving Throws Int +5, Wis +4 Senses passive Perception 11 Languages Common, Elvish Challenge 2 (450 XP) Actions Arcane Bolt. Ranged Spell Attack: +5 to hit, range 120 ft., one target. Hit: 10 (3d6) force damage.”

REF_010A sentence instead of a stat block

“A dragon breathes fire on the party.”

Monster Math

Numbers That Follow From Others

Much of a stat block is arithmetic on a few choices: ability scores, size, hit dice and challenge rating. These are the relationships the check recalculates, the ones most often wrong in homebrew.

01 / ABILITY

Ability modifier

Score minus 10, halved and rounded down.

“What modifier does 15 give?”

02 / HIT

Hit die by size

Tiny d4, Small d6, Medium d8, Large d10, Huge d12, Gargantuan d20.

“Which die does a Large creature use?”

03 / AVERAGE

Average hit points

The dice average, rounded down, plus Constitution per die.

“What does 6d8 + 6 average?”

04 / PROFICIENCY

Proficiency bonus

+2 up to CR 4, then +1 every four ratings, to +9 at CR 29–30.

“What is it at CR 5?”

05 / XP

XP by challenge

Fixed by the rating, from 10 XP at CR 0 to 155,000 at CR 30.

“How much XP is CR 1?”

06 / ATTACK

Attack bonus

Proficiency plus Strength or Dexterity, or the casting ability.

“PB +2, STR +3: what to hit?”

07 / SAVING

Saving throws and skills

Ability modifier plus proficiency; expertise doubles it.

“DEX +2, PB +2, expertise?”

08 / PASSIVE

Passive Perception

10 plus the Perception bonus, or 10 plus Wisdom.

“WIS +1 and no skill?”

The Three Layouts It Reads

Stat blocks are written in a few common shapes, and the reader handles all of them without being told which, so you can paste from wherever the monster lives.

Plain SRD Style

One line per field, such as Armor Class 15, with abilities on one line and a plain Actions heading.

Homebrewery Markdown

A blockquote with bold field names, an ability table and bold-italic entry names.

2024 Layout

AC and Initiative together, abilities one per line with modifier and save, and CR with XP and PB.

Homebrew Tips

Habits that make homebrew monsters easier to run at the table and easier for others to trust.

Tip 01

Write Formulas

Give hit points and damage with their dice so they can be checked.

Tip 02

Check After Tweaks

Changing one score can change five other numbers.

Tip 03

Match Size and Dice

A Large creature with d8 hit dice is easy to miss.

Tip 04

Keep Original Names

Name actions clearly; the check reports them by name.

Tip 05

Export Clean Copies

Use the Markdown view for documents and handouts.

Who Uses a Stat Block Checker

Anyone who writes, edits or converts monsters and wants the numbers right before players meet them.

Game Masters

Check homebrew foes before a session.

Adventure Writers

Proof stat blocks before publishing.

Converters

Move monsters between layouts and tools.

Tool Builders

Get structured JSON from text blocks.

Editors

Spot arithmetic slips in submitted content.

Stat Block Pitfalls

The errors that turn up most often in homebrew and converted monsters, and that the check reports.

Tip 01

Stale Modifiers

Changing a score but not the modifier written beside it.

Tip 02

Wrong XP

XP copied from a neighbouring challenge rating.

Tip 03

Missing CON Bonus

Hit dice without the Constitution bonus per die.

Tip 04

Attack Bonus Drift

To-hit bonuses that ignore a changed ability score.

Tip 05

Passive Perception

Forgetting the Perception skill when working it out.

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