The Core Mechanic: Whenever you attempt an action that has some chance of failure, you roll a twenty-
- Roll a d20.
- Add any relevant modifiers.
- Compare the result to a target number (usually a “difficulty check” [DC], the opponent’s armor class in the case of attacking another person, or another skill check roll provided by your DM)
If the result equals or exceeds the target number, your character succeeds. If the result is lower than the target number, you fail.
Dice rolls are described with expressions such as “3d4+3,” which means “roll three four-
d%: Percentile dice work a little differently. You generate a number between 1 and 100 by rolling two different ten-
In general, if you wind up with a fraction, round down, even if the fraction is one-
Exception: Certain rolls, such as damage and hit points, have a minimum of 1.
Sometimes a rule makes you multiply a number or a die roll. As long as you’re applying a single multiplier, multiply the number normally. When two or more multipliers apply to any abstract value (such as a modifier or a die roll), however, combine them into a single multiple, with each extra multiple adding 1 less than its value to the first multiple. Thus, a double (×2) and a double (×2) applied to the same number results in a triple (×3, because 2 + 1 = 3).
When applying multipliers to real-