Ability Bonus stacking?

[Uhtred]

I'm AFB at the moment and figured I'd double check to make sure it was kosher: the +2 to an ability score from an Ioun Stone would stack with the bonuses granted by, say, a Belt of Giant Strength, right? Since having a Belt of Giant Strength doesn't mean that a Bull Strength potion has no effect on you, I'd assume it does, but to be honest I don't actually understand Ioun Stones very well, and I don't want to be cheating, even out of ignorance. Thanks!

[AmberVael]

the +2 to an ability score from an Ioun Stone would stack with the bonuses granted by, say, a Belt of Giant Strength, right?
Nope.

Since having a Belt of Giant Strength doesn't mean that a Bull Strength potion has no effect on you
It does mean that, actually.


There's one key bit you're looking for when trying to figure out if bonuses stack, and that's the type of bonus it is. Different types of bonus stacks. Untyped bonuses stack. But two bonuses of the same specific type (or from the same source) don't stack.

A Belt of Giant Strength (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/a-b/belt-of-giant-strength) offers an enhancement bonus to strength.

A Bull's Strength (http://www.d20pfsrd.com/magic/all-spells/b/bull-s-strength) spell (or a potion granting the effects of such a spell) also offers an enhancement bonus to strength.

A pale blue rhomboid ioun stone (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/h-l/ioun-stones/pale-blue-rhomboid-ioun-stone) or similar ioun stones also offer enhancement bonuses to the ability scores they boost.

As such, only the highest of these bonuses will apply to you if you have more than one of them.

Just to give an example that would stack, the Righteous Might (http://www.d20pfsrd.com/magic/all-spells/r/righteous-might) spell offers a size bonus to Strength, and so would stack with any of the above methods.

[noob]

Is all those bonuses of the same kind or of different kinds.
If they are of the same kind you use only the highest one but the others exists and if the strongest one ends the others keeps existing but the applied bonus might be lower since now the strongest one is another one
(Got sword saged.)

[Psyren]

Is all those bonuses of the same kind or of different kinds.

They're all enhancement; AmberVael is correct, they won't stack.

Another source of strength that will stack is a barbarian's rage, which is a morale bonus, or an alchemist's mutagen, which is an alchemical bonus.

[Uhtred]

So a Barbarian's morale bonus to strength from rage would stack with a belt of giant strength, but he couldn't down a potion of bull strength and have it enhance him, since the belt was doing that already. He could do a potion of enlarge person, since that grants a size bonus. Hmmm. Interesting. Our group has always been fairly lax with ability score items, IDK if telling anyone but my DM will hurt things more than it helps. RAW, we've been doing it wrong, but we've been having a good time and there's been a point to spending the gold we earn. Hmm.

Swordsage'd. Drat.

[grarrrg]

with a belt of giant strength, but he couldn't down a potion of bull strength and have it enhance him, since the belt was doing that already

Well, if the Belt was only giving a +2 Enhancement bonus, then drinking the Potion of Bull's Strength would give you an "extra" +2 putting you at +4 total (same type > use larger bonus).

But if the Belt is a +4 or +6 version, then you are correct and the potion would do nothing.