I am confused about base attack bonus progression when two classes share the same advancement table. Basically, the PHB states that there are classes that share the good, average, and poor advancements, but it does not specify if that means they just refer to that table for individual class advancement, or if they share actual progression.

So the TLDR is this: If there is a level 2 character with 1 cleric/1 rogue, does it have +0 or +1 BAB?


2 Answers 2


It depends on the rules your DM wants to use. The Player’s Handbook is ambiguous, but most tables seem to do the simplest thing and just read the values from the two tables and add them together. Since those values are obtained by rounding down, this method has been known as the “round before adding” method, though a lot of people will just claim it is the default method or the PHB method.

That’s because it is contrasted with a variant proposed by Unearthed Arcana, the “fractional” (or “round after adding”) method. Since this is a variant, this is claimed as evidence that the default is the “round before adding” method. Personally, I agree with you that the Player’s Handbook is ambiguous, and I know a lot of people who have, without ever seeing UA, used “round after adding” just assuming it was what the PHB meant. Either way, this approach handles multiclassing between good (½ level + 2) and poor (⅓ level) save progressions, and medium (¾ level) and poor (½ level) BAB progressions, so your cleric 1/rogue 1 has a BAB of ¾×1 + ¾×1 = 1½ which rounds down to 1, while a cleric 1/wizard 1 would have a BAB of ¾×1 + ½×1 = 1¼ which also rounds down to 1 (but as more levels are gained, falls behind).

Ultimately, I strongly recommend the “fractional”/“round after adding” variant, or as I like to call it, the sane way of doing things. While the round-before approach is simpler, it’s not much simpler, and it produces very wonky numbers that are inappropriate. I typically combine this with a houserule saying that you do not get repeated +2’s for having multiple classes with the same good saves (e.g. a barbarian 1/fighter 2 should not have +5 base Fortitude any more than he should have +0 base Reflex—under my rules, he would have +3 base Fortitude and +1 base Reflex).

This produces the best numbers (as in, most similar to single-classed characters of the same level). It also allows you to simply just add together all your levels of a given progression, and just use that number off the table. For example, a cleric/rogue has the same BAB as a cleric or a rogue would have at the same (combined) level, and a cleric/wizard would have the same base Will as a cleric or wizard would. You do have to do a little bit of math to handle cases of mixed progressions, but it’s a small price to pay for avoiding the weird numbers that you get otherwise, which can cause awkwardness and annoyances in play.

The choice, however, has to be agreed upon by the group, so that everyone (PCs and NPCs) are doing the same thing. A player cannot unilaterally decide which method to use for his or her character without ensuring it matches how the rest of the game is being played.

An example of each. The \$\lfloor\ \rfloor\$ symbols mean “round down” whatever is between them.

\begin{array}{l|r|r} \text{Example} & \text{Round-Before} & \text{Round-After} \\ \hline \text{Cleric 1/Rogue 1 BAB} & \lfloor \frac{3}{4} \left(1\right) \rfloor + \lfloor \frac{3}{4} \left(1\right) \rfloor = & \lfloor \frac{3}{4} \left(1\right) + \frac{3}{4} \left(1\right) \rfloor = \\ & \lfloor 0.75 \rfloor + \lfloor 0.75 \rfloor = & \lfloor 0.75 + 0.75 \rfloor = \\ & 0 + 0 = & \lfloor 1.5 \rfloor = \\ & 0 & 1 \end{array}



Both Clerics and Rogues use the 3/4 level BAB progression (or average). When you multiclass, you only receive the benefits of the level that you take. For the levels you mention, that benefit is a +0 with regards to BAB.

So for your hypothetical character, they have +0 BAB, but they get the class features of a 1st level Cleric and a 1st level Rogue which includes a +2 on Reflex and Will saves.

Upon taking another level of either, their BAB will increase by +1. So if this character is evenly split between the two classes, they will have a +2 BAB by level 4 since the BAB is additive.

  • \$\begingroup\$ So you are of the opinion that although the classes share a progression table, they track their individual progression separately. Versus the alternative where if a progression table is shared, then the levels of all relevant classes are combined to advance on that table. \$\endgroup\$ Apr 13, 2017 at 19:36
  • \$\begingroup\$ This is how I've always done it, but as KRyan said, there's ambiguity in the rules. I don't have a PHB in front of me for rules citations, but by doing things in this manner, my thought process was that it simplified how to handle this scenario. Essentially, it made extensive multi-classing sacrifice offense (in the form of BAB) for specific defense (in the form of high specific saves). I can't comment on whether this is 'balanced', but 3.5 is unbalanced to the point of if you care a lot about balance, then you should play a different game. \$\endgroup\$ Apr 13, 2017 at 19:41
  • \$\begingroup\$ Wow. I didn't even know there was a controversy. This is how everyone I've ever played with understood it, too, including total strangers. Enjoy your upvote, and I join you in wondering at the downvotes! \$\endgroup\$ Apr 13, 2017 at 20:25
  • \$\begingroup\$ @HeyICanChan I'm really hoping someone gives me a reason for them, too. To the best of my knowledge, nothing I've said is wrong, it's just weird. Just like 3.5. \$\endgroup\$ Apr 13, 2017 at 20:58
  • \$\begingroup\$ Contrary to others experiences, every table I've ever experienced (played at, observed at, casually overlooked, over the internet, over the phone, groups in multiple states, groups in other countries) has used this method as the default. You take a level, you add whatever you get as specified in the level. It is entirely possible to have a 20th level character with +0 BAB, for example. \$\endgroup\$
    – nijineko
    Apr 14, 2017 at 0:11

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