Monster CR Calculator
Estimate a D&D 5e monster's Challenge Rating (CR) based on its Armor Class, Hit Points, Attack Bonus, and average damage per round.
Fill in the fields above and click Calculate.
Formula (DMG p.274–275)
1. Defensive CR — Look up raw CR from HP table. Adjust: for every 2 points AC differs from expected AC at that CR, shift CR ±1.
2. Offensive CR — Look up raw CR from DPR table. Adjust: for every 2 points Attack Bonus (or Save DC) differs from expected at that CR, shift CR ±1.
3. Final CR = (Defensive CR + Offensive CR) ÷ 2, rounded to nearest valid CR value.
Valid CRs: 0, 1/8, 1/4, 1/2, 1–30.
Assumptions & References
- Based on the Dungeon Master's Guide (5e), pp. 274–275, "Creating a Monster" tables.
- DPR should reflect the monster's average damage over a full round, including all attacks or multiattack.
- If the monster uses both attack rolls and saving throws, enter the higher of Attack Bonus or Save DC.
- Resistances, immunities, legendary actions, and special traits (e.g. regeneration) may further adjust CR — this tool covers the core stat-based estimate only.
- HP should be the average of the monster's hit dice expression (e.g. 6d8+12 → 39).
- XP values are from DMG Table: "Experience Points by Challenge Rating."