DnD Ability Scores and Modifiers

Ability scores are the six numerical foundations that define every character in Dungeons & Dragons — Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. Each score generates a modifier, the number that actually gets added to dice rolls. These two layers work together constantly, and getting them confused is one of the most common stumbling blocks at any table.

Definition and scope

Six scores. Six modifiers. The scores run from 1 to 20 for most player characters, though monsters and exceptional characters can exceed that ceiling. A score of 10 is considered the human average — functional, unremarkable, the statistical baseline that the entire system is built around.

The modifier is what matters in play. Every check, attack roll, and saving throw calls for a modifier, not the raw score. The formula is straightforward: subtract 10 from the score, divide by 2, and round down. A score of 14 yields a +2 modifier. A score of 9 yields a −1 modifier. A score of 18 — the highest most characters can achieve at creation through standard methods — yields a +4 modifier.

The six ability scores and their primary domains break down as follows:

1. Strength — physical power, melee attacks, carrying capacity
2. Dexterity — agility, ranged attacks, initiative, Armor Class (for light armor wearers)
3. Constitution — endurance, hit point maximum, concentration saving throws
4. Intelligence — memory, reasoning, arcane magic (Wizards rely on this)
5. Wisdom — perception, insight, divine attunement (Clerics and Druids key off this)
6. Charisma — force of personality, social interactions, Sorcerer and Bard spellcasting

These definitions come directly from the Systems Reference Document 5.1 published by Wizards of the Coast under the Creative Commons Attribution 4.0 license.

How it works

The modifier conversion table is one of the first things worth memorizing. Starting from the bottom: a score of 1 yields a −5 modifier, the lowest possible. Every 2-point increase in the score raises the modifier by 1. Scores 10 and 11 both produce a +0 modifier, which sometimes surprises new players expecting a +1 from 11.

This pairing structure — two scores to one modifier — explains why odd-numbered scores have a specific strategic implication. Raising a 13 Constitution to 14 improves the modifier from +1 to +2. Raising it from 12 to 13 does nothing to the modifier at all. At character creation and level-up, this is worth tracking carefully.

Modifiers appear in three major contexts within the rules:

• Ability checks: Roll 1d20, add the relevant modifier, compare to a Difficulty Class (DC). A DC 15 check against a Charisma (Persuasion) skill adds both the Charisma modifier and, if proficient, the character's proficiency bonus.
• Attack rolls: Roll 1d20, add the relevant ability modifier (Strength for most melee, Dexterity for ranged and finesse weapons), plus proficiency bonus if proficient with the weapon.
• Saving throws: Roll 1d20, add the relevant modifier (and proficiency bonus if proficient in that saving throw), compare to the effect's DC.

For a deeper look at how these mechanics interact in practice, the how it works page covers the full dice resolution sequence.

Common scenarios

The score-versus-modifier distinction trips up players most often in three situations. First, some class features reference the score directly. A Barbarian's Unarmored Defense adds the Constitution modifier to AC — not the score. A feature that grants a Constitution score increase of 2 is doing something structurally different from granting a +2 to the modifier.

Second, ability score improvements at certain levels (every 4 levels for most classes, per the Player's Handbook) add 2 points to a score — which may or may not improve the modifier, depending on whether the score is odd or even before the improvement.

Third, spells and conditions sometimes set a score to a fixed number. The spell Enhance Ability grants advantage on checks, while Feeblemind reduces Intelligence and Charisma scores to 1, which produces a −5 modifier on any check using those scores. That −5 is severe enough to make many tasks effectively impossible without magical aid.

More edge cases and table-specific questions are addressed in the DnD frequently asked questions section.

Decision boundaries

The practical question at character creation is which scores to prioritize. This depends on class, but a few structural rules hold across most builds.

Primary vs. secondary scores: Every class has one or two scores that govern spellcasting, attack rolls, or core class features — these are primary scores and should sit at 16 or higher, ideally 17 if a +1 racial bonus will push them to 18. Secondary scores (often Constitution for concentration and hit points) typically land in the 14–16 range. Tertiary scores can be left at 10 or lower without significant mechanical cost.

The odd-score trap: Leaving a primary score at 15 instead of pushing it to 16 costs 1 modifier point — roughly equivalent to permanently losing one point of average damage per attack, or failing checks that would otherwise succeed 5% more of the time.

Score generation method matters: The standard array (15, 14, 13, 12, 10, 8) and point buy each impose different ceilings and constraints than rolling 4d6 drop the lowest. A rolled 18 requires no investment; a point-buy 15 costs 9 of the 27 available points. These tradeoffs are discussed further in the key dimensions and scopes of DnD page.

The floor matters too. A score of 8 produces a −1 modifier, which is a minor penalty the game's bounded accuracy system can absorb. A score of 6 (−2) starts to affect saving throws and occasional checks in meaningful ways. Score dumping — deliberately minimizing scores to maximize others — is a legitimate optimization strategy, but scores below 8 carry real in-play consequences that extend beyond numbers.