Attacks And Ac
Every attack in Pathfinder follows the same core pattern: roll a d20, add your attack bonus, and compare the result to the target's Armor Class (AC). Meet or beat it and you hit; fall short and you miss. A natural 20 always hits and potentially threatens a critical; a natural 1 always misses regardless of modifiers.
The Attack Roll
Attack roll = d20 + attack bonus vs. target AC
Your attack bonus is the sum of several components that vary by attack type:
| Component | Melee | Ranged | Notes |
|---|---|---|---|
| Base Attack Bonus (BAB) | ✓ | ✓ | Granted by class and level. Fighters gain +1/level; Wizards +1 per 2 levels. |
| STR modifier | ✓ | — | Added to melee attack rolls. Penalty applies to ranged attacks only if negative. |
| DEX modifier | — | ✓ | Added to ranged attack rolls. Also applies to melee with Weapon Finesse (light weapons). |
| Size modifier | ✓ | ✓ | Small: +1. Large: −1. Huge: −2. See Size & Reach. |
| Misc bonuses | ✓ | ✓ | Enhancement (magic weapon), circumstance, morale, luck, etc. Most stack; same type doesn't. |
| Range penalty | — | ✓ | −2 per range increment beyond the first. Far Shot halves this penalty. |
Iterative Attacks
When your BAB reaches +6, you gain a second attack at BAB −5. A third opens at +11 (BAB −10) and a fourth at +16 (BAB −15). You can only make all your iterative attacks during a full attack action — a standard attack action gives you only one.
| BAB | Iterative attack bonuses |
|---|---|
| +1 to +5 | One attack at full BAB |
| +6 to +10 | Two attacks: full BAB / BAB −5 |
| +11 to +15 | Three attacks: full / −5 / −10 |
| +16 to +20 | Four attacks: full / −5 / −10 / −15 |
Natural 20 and Natural 1
Natural 20 — Automatic Hit
A roll of 20 on the die always hits regardless of the target's AC or your modifiers. It also threatens a critical hit.
Confirming: Roll again at the same bonus. If the confirmation roll also hits the target's AC, the critical is confirmed and damage is multiplied by the weapon's critical multiplier (×2 for most weapons). If it misses, the attack still hits but deals normal damage.
Natural 1 — Automatic Miss
A roll of 1 on the die always misses regardless of the target's AC or your attack bonus. It does not automatically cause a fumble or weapon drop in the core rules — that is a variant rule some GMs add.
Armor Class (AC)
AC = 10 + armor bonus + shield bonus + DEX modifier + size modifier + other bonuses
| Bonus type | Stacks? | Source |
|---|---|---|
| Armor | No | Worn armor. Only the highest armor bonus applies if wearing multiple pieces. |
| Shield | No | Held shield. Only one shield bonus applies at a time. |
| DEX modifier | — | Capped by armor's Max DEX value. Lost when flat-footed. |
| Natural armor | No | Monsters, races with thick hide, barkskin spell. Enhancement to natural armor stacks with the base natural armor bonus. |
| Deflection | No | Ring of protection, shield of faith. Applies against touch attacks. |
| Dodge | Yes | Dodge feats, haste, Total Defense. Multiple dodge bonuses stack with each other. |
| Size | — | Small: +1. Large: −1. Huge: −2. Same modifier applies to attack rolls. |
| Insight / Luck / Sacred / Profane | No | Circumstantial bonuses from spells and class features. Only the highest of each type applies. |
Touch AC and Flat-Footed AC
Touch AC
Used when the attack only needs to make contact — touch spells, ray spells, some combat maneuvers. Armor, shield, and natural armor bonuses do not apply to touch AC. DEX, deflection, dodge, and size still apply.
Used against attacks before you have acted in combat (or when caught unaware). DEX and dodge bonuses do not apply to flat-footed AC. Uncanny Dodge prevents a character from losing their DEX bonus when flat-footed.
Damage
On a successful hit, roll the weapon's damage dice and add your STR modifier (melee) or — for thrown weapons — your STR modifier. Ranged weapons generally do not add STR unless they have a minimum strength (composite bows) or are thrown.
- Two-handed weapons: add 1½× STR modifier to damage (round down on fractions).
- Off-hand weapons: add only ½× STR modifier to damage (round down).
- Negative STR modifier: always applies to melee damage, even with two-handed weapons (no ½× or 1½× reduction on penalties).
- Minimum damage: a successful hit always deals at least 1 point of damage, even if all modifiers reduce the total to 0 or less.
- Critical hit damage: roll all damage dice again (weapon dice + STR modifier for each roll) and add the totals. Bonus damage dice (sneak attack, flaming) are not multiplied unless the ability specifically says so.
Attack & AC Calculator
Total Attack Bonus
+0
BAB +0, ability +0, size +0, misc +0
Full AC
10
Touch AC
10
Flat-Footed AC
10