Pathfinder Ability Scores: Rules and Modifiers

Six numbers sit at the foundation of every Pathfinder character — and nearly every mechanical outcome in the game flows through them in some way. This page covers how ability scores are defined in the Pathfinder Roleplaying Game (first edition, published by Paizo), how modifiers are calculated, and where those numbers matter most during play. Whether a character is attempting to climb a cliff, resist a poison, or land a critical spell, one of these six scores is almost certainly involved.

Definition and scope

Ability scores in Pathfinder measure the six core attributes that define a character's fundamental capabilities: Strength (STR), Dexterity (DEX), Constitution (CON), Intelligence (INT), Wisdom (WIS), and Charisma (CHA). Every player character, non-player character, and monster in the game has these six values, though the methods for generating them can vary.

The standard value for a typical adult human commoner is 10 or 11 in each score — a deliberate design baseline established in the Pathfinder Core Rulebook (Paizo, 2009). Heroic player characters start meaningfully above that baseline, and the scores keep growing through levels, magic items, and class abilities.

Each score has an associated ability modifier, and that modifier — not the raw score — is what almost all game mechanics actually use. The modifier is derived from the score using a fixed formula: subtract 10, then divide by 2, rounding down. A score of 16 produces a +3 modifier. A score of 7 produces a –2 modifier. The symmetry is clean, and the math is fast once it becomes habit.

How it works

The modifier formula produces a simple, predictable scale:

1. Score 1: –5 modifier (effectively incapacitated in that attribute)
2. Score 8–9: –1 modifier (below average but functional)
3. Score 10–11: +0 modifier (the human baseline)
4. Score 16–17: +3 modifier (notably gifted)
5. Score 18: +4 modifier (the starting cap for most point-buy builds)
6. Score 20: +5 modifier (common with racial bonuses applied)
7. Score 36+: +13 modifier and beyond (found on powerful monsters)

When a character rolls a d20 for an attack, a skill check, or a saving throw, the relevant ability modifier is added to that result. A Wizard with INT 20 adds +5 to Knowledge checks and spell DCs tied to Intelligence — that single five-point swing can be the difference between success and failure against a Difficulty Class (DC) of 18.

Scores increase through level progression (every 4 levels, one score rises by 1, per Core Rulebook Chapter 3), through magic items like a Belt of Giant Strength, and through class features such as the Barbarian's ability to temporarily boost Strength during rage. Ability drain — a more severe condition than ability damage — reduces the actual score permanently until magically restored. Damage only reduces a score temporarily.

The Pathfinder rules system traces its lineage to the System Reference Document 3.5 (Wizards of the Coast), and the modifier formula has been consistent across that entire family of rules. That consistency means players moving between editions will find the math familiar even when the surrounding rules shift.

Common scenarios

Combat: A Fighter with STR 18 (+4) adds that +4 to melee attack rolls and to damage. That same modifier also applies to Combat Maneuver Bonus (CMB), which governs grapple, trip, and disarm attempts.

Spellcasting: A Cleric's spell save DCs are calculated as 10 + spell level + WIS modifier. At WIS 22 (+6), a 5th-level spell DC reaches 21 — a number that most monsters at that tier will fail roughly half the time.

Saving throws: Fortitude saves add the CON modifier, Reflex saves add DEX, and Will saves add WIS. A character with CON 8 has a –1 penalty on every Fortitude save for their entire career unless the score improves.

Skill checks: Each of the game's roughly 35 skills keys off one of the six ability scores. Stealth runs off DEX; Perception off WIS; Bluff, Diplomacy, and Intimidate off CHA. A social character investing in CHA 20 gets a +5 baseline on three of the game's most commonly contested skills simultaneously.

Decision boundaries

Point-buy character creation — the most common organized play format, used in Pathfinder Society (Paizo's official organized play program, which standardizes 15-point or 20-point builds) — forces meaningful trade-offs between scores. Raising a score from 14 to 16 costs 3 build points; from 16 to 18 costs 4. Those costs accelerate sharply, making a single score above 18 expensive enough to starve other attributes.

The critical decision boundary sits between 12 and 13 in a secondary score. At 12, the modifier is +1. At 13, it is still +1. But many feats — particularly Combat Expertise and the Improved Maneuver chain — require an INT score of exactly 13, not a +1 modifier. The score itself, not the modifier, is the threshold. That distinction catches new players regularly.

A score below 10 in a dump stat is common optimization practice, but CON is the score most dangerous to reduce. Every point of CON below 10 reduces hit points retroactively across all existing levels — a character who drops CON from 10 to 8 at level 8 loses 8 hit points immediately. That arithmetic makes CON dumping genuinely costly in ways that dumping CHA or INT rarely is. The full rules reference on this site covers ability damage and drain mechanics in greater depth.