Wildshape stacking

[Yogibear41]

I am a 6th level druid. I then take 3 levels in Wildshape Ranger. What is the HD limit on the forms I can wildshape into? 6 or 9?

Same question, but I am now a 5th level Wildshape ranger in addition to my 6 druid levels.

[Vaern]

In general, ask your DM. Mixing variants with core classes to have multiple instances of the same ability can get a bit wonky.

I'd personally say that the two classes don't stack and progress entirely separately from each other. At druid 6/ranger 3, you'd be able to wild shape twice with a 6 HD limit. At druid 6/ranger 5, you'd be able to wild shape twice per day with a 6 HD limit and once per day with a 5 HD limit. Kind of like how a multiclass wizard/sorcerer will have access to one spell list from two different sources of spellcasting, but interact with that spell list through two separate arrays of spell slots and at two different caster levels.

The ranger's wild shape variant restricts it to small and medium animals only. They don't gain the options of additional sizes, plant wild shape, or elemental wild shape as they level up. Allowing ranger levels and druid levels to stack would result in the character either gaining options that the ranger is not allowed to gain, or losing out on options that the druid is supposed to have; thus, the two classes should not stack for the purpose of wild shape progression. And if the two do not stack with each other for progression then there's no reason for them to stack for just the purpose of max HD.

That's my take on it, anyway. Having never actually played a druid myself, though, I expect someone else will pop in soon with better insight on the subject. A reasonable DM could likely be convinced to establish a house rule that allows the classes to stack for the purpose of determining max HD, or maybe homebrew a quick feat for this particular circumstance that allows them to stack, but as far as I can tell there's no reason to assume that this is the standard.

[rickayelm]

Wild shape ranger says that it advances HD of other wild shape class but not size or type. You need to actually have wild shape though, since a wild shape ranger gets it at level 5 just like a druid, a druid 6 ranger 3 would just wild shape as a druid 6.

[SirNibbles]

In general, ask your DM. Mixing variants with core classes to have multiple instances of the same ability can get a bit wonky.

I'd personally say that the two classes don't stack and progress entirely separately from each other. At druid 6/ranger 3, you'd be able to wild shape twice with a 6 HD limit. At druid 6/ranger 5, you'd be able to wild shape twice per day with a 6 HD limit and once per day with a 5 HD limit. Kind of like how a multiclass wizard/sorcerer will have access to one spell list from two different sources of spellcasting, but interact with that spell list through two separate arrays of spell slots and at two different caster levels.

The ranger's wild shape variant restricts it to small and medium animals only. They don't gain the options of additional sizes, plant wild shape, or elemental wild shape as they level up. Allowing ranger levels and druid levels to stack would result in the character either gaining options that the ranger is not allowed to gain, or losing out on options that the druid is supposed to have; thus, the two classes should not stack for the purpose of wild shape progression. And if the two do not stack with each other for progression then there's no reason for them to stack for just the purpose of max HD.

That's my take on it, anyway. Having never actually played a druid myself, though, I expect someone else will pop in soon with better insight on the subject. A reasonable DM could likely be convinced to establish a house rule that allows the classes to stack for the purpose of determining max HD, or maybe homebrew a quick feat for this particular circumstance that allows them to stack, but as far as I can tell there's no reason to assume that this is the standard.

Agreed.

First, Wild Shape Ranger doesn't gain Wild Shape until 5th level so it can't possibly stack at 3rd level.

Second, Neither Wild Shape Ranger nor Druid mention anything akin to 'effective Druid level' for the purpose of Wild Shaping. Your Druid level is your Druid level and it determines your Wild Shape from Druid. Your Ranger level is your Ranger level and it determines your Wild Shape from Ranger.

[Biggus]

Wild shape ranger says that it advances HD of other wild shape class but not size or type.

Does it? Where are you seeing that? All I can see is:

https://www.d20srd.org/srd/variant/classes/variantCharacterClasses.htm#ranger

[Vaern]

Wild shape ranger says that it advances HD of other wild shape class but not size or type.

Animal companion specifically says that level stacks with your level in other classes to determine the attributes of your animal companion; neither the wild shape ability nor the ranger variant includes such a clause allowing ranger and druid levels to stack.
Note that I am looking at the Unearthed Arcana's simple variant which replaces the ranger's combat style with wild shape, though. If there's a second, more detailed wild shape variant in another book that I don't know of and I'm looking at the wrong one, please feel free to correct me.

[SirNibbles]

I'm seeing the same exact readings as Vaern and Biggus (Unearthed Arcana, page 58) with no mention at all of stacking. Another variant class that gets Wild Shape, the Wild Monk (Dragon Magazine #324, page 97) specifically mentions that the Wild Shape abilities don't stack in that case. You could easily apply that reading to Wild Shape Ranger/Druid.