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 character Enhancements are almost always untyped, and thus stack. They are not automatically "enhancement bonuses". Note, however, that some Enhancement lines are mutually exclusive and cannot stack because they cannot both be taken.
 * Damage Reduction does not stack, except for the added DR that comes from active blocking.
 * Temporary hit points do not stack.