D&D 5e Ability Score Modifier Calculator
Calculate the ability score modifier for any D&D 5th Edition ability score (Strength, Dexterity, Constitution, Intelligence, Wisdom, Charisma).
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Formula
Modifier = floor((Ability Score − 10) ÷ 2)
Examples:
- Score 10 → floor((10−10)/2) = +0
- Score 16 → floor((16−10)/2) = +3
- Score 8 → floor((8−10)/2) = −1
- Score 1 → floor((1−10)/2) = −5
- Score 30 → floor((30−10)/2) = +10
Assumptions & References
- Formula sourced from the D&D 5th Edition Player's Handbook, Chapter 1 (p. 13).
- Standard ability scores range from 1 to 20 for player characters; 30 is the maximum possible (e.g., some deities/monsters).
- The floor function rounds down toward negative infinity (e.g., score 9 → floor(−0.5) = −1).
- Modifiers range from −5 (score 1) to +10 (score 30).
- This calculator applies to all six core abilities: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma.
- Proficiency bonuses, racial bonuses, and magical effects that alter the score are not included here — only the base modifier is calculated.