If the attack roll result equals or exceeds the target's AC, the attack is successful, and the attacker deals damage to the defender. Roll the appropriate damage for the attacker's weapon. The damage is deducted from the target character's current hit points.
If penalties to damage bring the damage result below 1, a hit still deals 1 point of damage.
When a character is fighting with two weapons deals damage with the extra attack, add only one-half of the character's Strength bonus.
When a character deals damage with a weapon that the character is wielding two-handed, the character adds one and one half times the character's Strength bonus. Light weapons don't get this higher Strength bonus when used two-handed.
An unarmed strike from a Medium-size character deals 1d3 points of damage (with a character's Strength modifier, as normal). A Small character's unarmed strike deals 1d2 points of damage. All damage is subdual damage. Unarmed strikes count as light weapons (for purposes of two-weapon attack penalties and so on).
A character can specify that it's unarmed strike will deal normal damage before it makes an attack roll, but the attack suffers a -4 penalty.
When a character makes an attack roll and gets a natural 20, the character hits regardless of the target's AC, and the character has scored a threat. The hit might be a critical hit (or “crit”). To find out if it's a critical hit, the character immediately makes a critical roll — another attack roll with all the same modifiers as the attack roll the character just made. If the critical roll also results in a hit against the target's AC, the character's original hit is a critical hit. If the critical roll is a miss, then the character's hit is just a regular hit.
A critical hit means that the attacker rolls for damage more than once, as indicated by the weapon description for the weapon that scored the threat, with all the attacker's usual bonuses, and add the rolls together to get total damage.
Exception: Bonus damage represented as extra dice is not multiplied when a character score a critical hit.
Sometimes a character's threat range is greater than 20. In such cases, a roll below 20 is not an automatic hit. Any attack roll that doesn't result in a hit is not a threat.
Some weapons, deal better than double damage with a critical hit.
Sometimes a character multiplies damage by some factor, such as when a character scores a critical hit. Roll the damage (with all modifiers) multiple times and total the results.