you will add the new bab to your existing bab, so lets say your multyclass or prestige class gives you a +1 bab then your new bab would be 7,2.
what ever the new bab is just add it on.
Hi.
Im bit confused how to count bab and base saves for characters multiclassing and taking levels in prestige classes.
For example a 6th lvl fighter has bab 0f +6/+1 and takes a level in duelist, how to calculate his new base attack bonus?
You add the BAB for all of the classes you have together. In your example, the +6 of the Fighter is added with the +1 from Duelist to get a total of +7 for your character's BAB.
Extra attacks come every time you reach a certain amount of total BAB that, when you subtract 5 from the lowest attack bonus you get still gives you a positive number. Examples really work best, here, because I'm not the best at explaining how it all works in my head without them.
The example 7th level Fighter/Duelist has a BAB of +7. 7-5=2, so he/she can make another attack with a +2 bonus, often denoted as +7/+2. Say he/she levels up and is now 11th level (Fighter 6/Duelist 5). Now they have a BAB of +11. 11-5=6, and 6-5=1, so he/she can make three attacks, the first with a +11 bonus, the second with a +6 bonus, and the third with a +1 bonus, often denoted as +11/+6/+1. That's before any other modifiers, naturally.
That help?
yup, just add them on, this can give you a nice little boost sometimes like gaining a +2 from a new save.
As for saves, remember that under Pathfinder rules prestige class save progression has been changed from 3.5 D&D.
Now, good saves in prestige classes start at +1, not +2 as in all the prestige classes from 3.5.
If you want to use any 3.5 prestige classes it's an easy fix:
Any save that started at +2 is a "good save". Change the first level bonus on any good save to +1. From that point foward it goes up by one every two levels (+2 at level 3, +3 at level 5, etc).
Any save that starts at +0 is a "poor save". Poor saves now actually progress a little better than they used to in 3.5 prestige classes. The first level of any poor save remains a +0, but at level two it progresses to a +1. From that point foward it goes up by one every three levels (+2 at level 5, +3 at level 8, etc).
You can easily see the new progressions in chapter 11 of the Pathfinder Core Rulebook.
I have not seen many characters that are higher then level 20. So, it depends on how your DM is handling post 20 levels. You may not get any additional BAB at all depending if the DM is using the 3.5 epic rules.
ignoring all of that. lets assume you are following the progression as stated in the character advancement rules.
Hit dice, base attack bonuses, and saving throws continue to increase at the same rate beyond 20th level, as appropriate for the class in question. Note that no character can have more than 4 attacks based on its base attack bonus.
A 20th level Archivist(3rd party) has a BAB of +10
A 20th level Knight(3rd party class) has a BAB of +20I assume from context that a 10th level "pale master" has a BAB of +5
This would leave you with a BAB progression of the following.
+35/+30/+25/+20