Pathfinder gameplay relies on numerous formulas for calculating stats, effects, and outcomes. This page compiles all essential formulas into a single reference, allowing gamemasters to easily locate what they need for swift and accurate gameplay.
Reference Tables and Modifiers
- Size Modifiers (Used to calculate AC, Attack rolls, and Stealth skill checks)
- Fine: +8
- Diminutive: +4
- Tiny: +2
- Small: +1
- Medium: +0
- Large: –1
- Huge: –2
- Gargantuan: –4
- Colossal: –8
- Special Size Modifiers (Used to calculate CMB and CMD)
- Fine: –8
- Diminutive: –4
- Tiny: –2
- Small: –1
- Medium: +0
- Large: +1
- Huge: +2
- Gargantuan: +4
- Colossal: +8
Formulas
Listed below are the formulas for each given context.
General Combat
- AC (Armor Class): 10 + Armor bonus + Deflection bonus + Dexterity modifier + Dodge bonus + Enhancement bonus + Natural Armor bonus + Shield bonus + Size modifier1
- Flat-Footed: 10 + Armor bonus + Deflection bonus + Enhancement bonus + Natural Armor bonus + Shield bonus + Size modifier1
- Touch: 10 + Deflection bonus + Dexterity modifier + Dodge bonus + Size modifier1
- Attacks
- Melee: 1d20 + BAB + weapon’s Enhancement bonus + Strength modifier + Size modifier1 vs target’s AC
- Ranged: 1d20 + BAB + weapon’s Enhancement bonus + Dexterity modifier + Size modifier1 vs target’s AC
- Touch: 1d20 + BAB + Strength modifier + Size modifier1 vs target’s touch AC
- Ranged Touch: 1d20 + BAB + Dexterity modifier + Size modifier1 vs target’s touch AC
- CMB (Combat Maneuver Bonus): BAB + Strength modifier + Dexterity modifier + Special Size modifier2 + Miscellaneous modifiers vs target’s CMD
- CMD (Combat Maneuver Defense): 10 + BAB + Strength modifier + Dexterity modifier + Special Size modifier2 + Miscellaneous modifiers
- Saving Throws
- Fortitude: 1d20 + Base Save bonus + Constitution modifier + Enhancement bonus + Sacred/Profane bonus + Insight bonus + Luck bonus + Trait bonus + Resistance bonus vs DC of the effect
- Reflex: 1d20 + Base Save bonus + Dexterity modifier + Enhancement bonus + Sacred/Profane bonus + Insight bonus + Luck bonus + Trait bonus + Resistance bonus vs DC of the effect
- Will: 1d20 + Base Save bonus + Wisdom modifier + Enhancement bonus + Sacred/Profane bonus + Insight bonus + Luck bonus + Trait bonus + Resistance bonus vs DC of the effect
- Status Effect: Dying (Negative HP)
- Stabilize: 1d20 + Constitution modifier – negative HP value penalty vs 10 (natural 20 is an automatic success)
- Failure: creature loses 1 HP
- Success: creature stabilizes; no longer loses 1 HP per round
- Stabilize: 1d20 + Constitution modifier – negative HP value penalty vs 10 (natural 20 is an automatic success)
Skill Checks
- Acrobatics
- Move through a threatened area: 1d20 + total Acrobatics bonus vs opponent’s CMD (at half speed; +10 to DC if moving at full speed)
- Failure: provoke an attack of opportunity from opponent
- Move through an enemy’s space: 1d20 + total Acrobatics bonus vs 5 + opponent’s CMD (at half speed; +10 to DC if moving at full speed)
- Failure: lose the move action and provoke an attack of opportunity from opponent
- Move through a threatened area: 1d20 + total Acrobatics bonus vs opponent’s CMD (at half speed; +10 to DC if moving at full speed)
- Knowledge
- Monster Lore: 1d20 + total Knowledge bonus vs 10 (5 for common or 15 for rare monsters) + CR of creature
- Applicable uses (gain knowledge about specific creature types)
- Arcana: constructs, dragons, and magical beast creature types
- Dungeoneering: aberrations and ooze creature types
- Local: humanoid creature types
- Nature: animals, fey, monstrous humanoids, plants, and vermin creature types
- Planes: outsider creature types
- Religion: undead creature types
- Traits to learn (but are not limited to):
- How many HD
- Type/s and Subtype/s
- Lowest Save
- Highest Save
- All weaknesses
- All resistances
- All immunities
- DR Type
- Does it have SR
- Main Attack
- Main Magic
- Secondary Magic
- Special Attacks (Trip, grapple etc. One per selection.)
- Special Abilities (Supernatural attacks, acid, poison etc. One per selection.)
- Modes of Movement (not speed)
- Speed
- Battle Tactics
- Pack or Solo
- Applicable uses (gain knowledge about specific creature types)
- Monster Lore: 1d20 + total Knowledge bonus vs 10 (5 for common or 15 for rare monsters) + CR of creature
- Spellcraft
- Identify spell being cast: 1d20 + total Spellcraft bonus vs 15 + spell level
Spellcasting
- Caster Level Checks
- Base: 1d20 + caster level vs DC (see below):
- Dispel Check: DC = 11 + the spell’s caster level
- Overcome SR (Spell Resistance): DC = target’s SR value
- Base: 1d20 + caster level vs DC (see below):
- Concentration Checks
- Base: 1d20 + caster level + casting modifier vs DC (see below):
- Cast defensively: DC = 15 + double spell level
- Injured while casting: DC = 10 + damage dealt + spell level
- Continuous damage while casting: DC = 10 + 1/2 damage dealt + spell level
- Affected by a non-damaging spell while casting: DC = DC of the spell + spell level
- Grappled or pinned while casting: DC = 10 + grappler’s CMB + spell level
- Vigorous motion while casting: DC = 10 + spell level
- Violent motion while casting: DC = 15 + spell level
- Extremely violent motion while casting: DC = 20 + spell level
- Wind with rain or sleet while casting: DC = 5 + spell level
- Wind with hail and debris while casting: DC = 10 + spell level
- Weather caused by spell: DC = see spell
- Entangled while casting: DC = 15 + spell level
- Base: 1d20 + caster level + casting modifier vs DC (see below):
- Spell DC: 10 + spell level of the spell + casting modifier