Damage

When your attack succeeds, you deal damage. The type of weapon used determines the amount of damage you deal. Effects that modify weapon damage apply to unarmed strikes and the natural physical attack forms of creatures.

Damage reduces a target’s current hit points.

Minimum Damage
If penalties reduce the damage result to less than 1, a hit still deals 1 point of damage. Exceptions are if the target has damage reduciton, or you are using the feat: Precision

Strength Bonus
When you hit with a melee or thrown weapon, including a sling, add your Strength modifier to the damage result. A Strength penalty or a bonus - only if you have the feat Bow Strength, applies on attacks made with any bow.

Off-Hand Weapon
When you deal damage with a weapon in your off hand, you add only ½ your Strength bonus.

Wielding a Weapon Two-Handed
When you deal damage with a weapon that you are wielding two-handed, you add 1½ times your Strength bonus.

Multiplying Damage
Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results. Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage.

Exception: Extra damage dice over and above a weapon’s normal damage are never multiplied.

Ability Damage
Certain creatures and magical effects can cause temporary ability damage (a reduction to an ability score).