Question: This is a mechanics question pertaining to the maximum allowed damage for the Paladin's *Divine Smite* ability.

> 
> **Divine Smite:** ...you can expend one [Spell Slot] to deal Radiant damage in addition to weapon damage. The extra damage is 2d8 for a
>  1st level slot, plus 1d8 for each spell level higher than 1st, to a
>  maximum of 5d8....
> 
> 
> 

**"...to a maximum of 5d8..."** is the part I'm having issues with figuring out how to rule.

Can the *extra* damage, beyond the 2d8 for filling a 1st level slot with the ability, be up to 5d8? Which would require a (Multiclass gained) spell slot of 6th level to add an extra 5d8 to the attack, making it 7d8 total (The default 2d8 + the maximum allowed extra of 5d8). *Or*, are the rules saying that the total allowed maximum damage can't exceed 5d8 total; which would only take a 4th level spell slot to add a max of 3d8 to the default 2d8?

2d8 + 3d8 = "to a maximum of 5d8" damage total?  

2d8 + "to a maximum of 5d8" extra total = 7d8 ?

My guess is the first choice, since without Multiclassing a Paladin can never have more than 5th level spell slots and could never have the 6th level slot required to add 5d8 to the attack. My PC differs though.

Answer: 
The maximum is on *all* the extra radiant damage that Divine Smite adds to your normal weapon damage, necessarily including the first 2d8 (emphasis mine):

> 
> […] you can expend one paladin spell slot to deal radiant damage to the target, **in addition** to the weapon's damage. **The extra damage is [a variable amount], to a maximum of 5d8.**
> 
> 
> 

The 5d8 maximum is a limit on the extra radiant damage that Divine Smite is adding to the weapon's damage.

(For *Improved* Divine Smite, see the question [Improved Divine Smite Differentiation](https://rpg.stackexchange.com/questions/70028/improved-divine-smite-differentiation).)
I've assumed that 5d8 was the maximum for the whole Divine Smite, not the extra damage. Maybe this isn't really a good answer, but I can't see why it'd be the other way given that multiclassing is optional at the DM's discretion. If it *was* the other way then at most you could only get 5d8 out of it with 4th level spell slots, and to get any higher the DM would have to allow multiclassing, and not every DM will have it in their game. Furthermore, it seems highly impractical to require leveling **another class** high enough to grant the character 6th level spell slots. 

Primary spellcasters give their full level towards the calculation, but secondary casters like Paladins only add half their level (rounded up I believe) to that. So you only have 4th level spell slots as a Paladin at 13th level and higher. For the spell slots you want here, the Paladin would have to multiclass into a Primary spellcaster for 4 levels, to get the **one** 6th level spell slot from there. That is all *if* multiclassing is allowed. And the end result is a 17th level character.

Actually, let's re-frame that whole thought. If you wanted to get maximum Divine Smite capability, you actually would try to multiclass very early on. The Paladin gets Divine Smite at 2nd level, where they get Spellcasting and 1st level Spell Slots. You could accomplish this feat of Divine Smite by taking 10 levels in a Primary spellcasting class, and then you'll still get 6th level spell slots. **That** would be the most efficient way of doing it, I suppose. 

I hope that answers your question thoroughly enough. It would be preposterous to require an optional feature, and at a *highly* impractical manner at that, to get the Maximum Power of your Divine Smiting capabilities. (*I feel like I really drifted off topic with that explanation of why it doesn't work.*) 

**So I hope we can assume that the total maximum is 5d8.**