Stack

Abilities or skills that "stack" add their effects together. For example, modifiers of +1 Save all and +2 Save against fear "stack" to create a total +3 to Save versus fear (in addition to the +1 to Save against everything else).

Abilities or skills that do not stack apply only the strongest effect. For example, having non-stacking +3 and +5 modifiers is only worth a +5 bonus.

Stacking follows a few predictable general rules:


 * Bonuses usually (but not always) have a keyword, such as "enhancement" or "resistance", identifying what type of bonus it is. Bonuses of the same type do not stack.
 * Dodge bonuses to AC are a partial exception to this. Dodge bonuses stack unless they're the same size and both come from worn items.
 * An enhancement bonus to AC on a suit of armor will stack with an enhancement bonus to AC on a shield.
 * Benefits from the same family, like Fortification or False Life, do not stack.
 * Untyped bonuses stack.
 * Penalties stack.
 * Bonuses from Enhancements stack. (NOTE: "Bonuses from Enhancements" and "enhancement bonuses" are not the same thing. Yes, it's confusing.)
 * Damage Reduction does not stack, except for the added DR that comes from active blocking.
 * Temporary hit points do not stack.