Rules Index | GM Screen

Chapter 9: Playing the Game / General Rules / Damage / Step 1: Roll the Damage Dice and Apply Modifiers, Bonuses, and Penalties

Doubling and Halving Damage

Source Core Rulebook pg. 451 1.1
Sometimes you’ll need to halve or double an amount of damage, such as when the outcome of your Strike is a critical hit, or when you succeed at a basic Reflex save against a spell. When this happens, you roll the damage normally, adding all the normal modifiers, bonuses, and penalties. Then you double or halve the amount as appropriate (rounding down if you halved it). The GM might allow you to roll the dice twice and double the modifiers, bonuses, and penalties instead of doubling the entire result, but this usually works best for single-target attacks or spells at low levels when you have a small number of damage dice to roll. Benefits you gain specifically from a critical hit, like the flaming weapon rune’s persistent fire damage or the extra damage die from the fatal weapon trait, aren’t doubled.