Let's go over the exceptions to the rules plus a few other things of note as we wrap up the article focused on this question: Does it Stack?
Exceptions to the Rules for Stacking Bonuses
As with many things in the D&D game, the general rules are simple -- it's the exceptions that become difficult. Let's look at a few.
Bonuses of the Same Type
As noted earlier, bonuses of the same type (and with the same name) don't stack, but that's not always true:
Circumstance Bonuses: Circumstance bonuses stack when they arise from different circumstances. For example, you might get a circumstance bonus to Move Silently checks when you're walking on a soft surface, such as sand or moss. You might also get a circumstance bonus to Move Silently checks when moving in a very noisy environment.
Dodge Bonuses: A dodge bonus affects your Armor Class. All dodge bonuses stack. Most bonus types have names so that you can tell which one you can stack. A dodge bonus is named so that you can tell when you get it and when you don't. For example, you can't use dodge bonuses when you're flat-footed or anytime you're denied a Dexterity bonus.
A bonus that doesn't have a name stacks with anything except itself. This is always true, but it's sometimes hard to remember. For example, many feats provide unnamed bonuses, so don't panic when you read a feat description and it provides a bonus without a name. An unnamed bonus from a feat stacks with any other bonus; however you can't stack that unnamed bonus if you take the feat twice.
Synergy Bonuses: What once was called a synergy bonus in the previous version of the D&D game is now just an unnamed bonus. For example, if you have 5 or more ranks in the Handle Animal skill, you get a +2 bonus on Ride checks and wild empathy checks. As an unnamed bonus, this stacks with other bonuses you might have to Ride checks or wild empathy checks.
Base Attack and Save Bonuses
The base attack bonus and base save bonuses a character gets from class levels -- or that a creature gets from its type and Hit Dice -- are not true bonuses at all. (That's one reason why base attack and save bonuses aren't mentioned in the Bonus Types section in Chapter 2 of the Dungeon Master's Guide.) This is a situation where the language of the game gets a little muddy. Base attack and save bonuses are called "bonuses" strictly as a matter of convenience, mostly because you write them down and use them just like a regular bonus.
You can treat a base attack bonus or a base save bonus just like an unnamed bonus, except that two or more base attack or save bonuses from different classes always stack. You cannot take a class twice and stack the base attack or base save bonuses from the class. Instead, you must add up all your levels in the class and use the appropriate base attack and base save bonuses for that level.
It's also important to remember that you don't get extra attacks when you add extra bonuses to a high base attack bonus. For example, if your base attack bonus from all your classes is +7, you can make two attacks when you use the full attack action (+7/+2). If you then add +3 points to your attacks from a high ability score and another +2 from an enhancement bonus on your weapon, you still get only two attacks, but you add that +2 and +3 (for a total of +5) to each attack (+12/+7).
Inherent Bonuses and Level-Based Ability Increases
When you have an inherent bonus to an ability score, you're limited to a +5 inherent bonus to any single ability score. Since an inherent bonus has a name, it won't stack with another inherent bonus (so be careful with those manuals and tomes). The ability score increase you get every four character levels is not an inherent bonus; the ability score you choose to increase just gets bigger.
A Final Word
That's about all there is. There's not much to stacking bonuses. Just remember the basic rules:
- Bonuses with different names stack.
- Bonuses with the same names overlap (don't stack)
- Bonuses with no names stack with any other bonuses (but not with themselves).
And remember the major exceptions:
- Dodge bonuses stack with each other.
- Circumstance bonuses stack when they arise from different circumstances.
About the Author
Skip Williams keeps busy with freelance projects for several different game companies and has been the Sage of Dragon Magazine since 1986. Skip is a co-designer of the D&D 3rd Edition game and the chief architect of the Monster Manual. When not devising swift and cruel deaths for player characters, Skip putters in his kitchen or garden (his borscht gets rave reviews).