I play a Tortle Draconic Bloodline sorcerer, and my DM and myself are scratching our heads on what its AC total should be.

The Draconic Bloodline sorcerer gets an AC of 13 + Dex, but Tortles get an AC of 17 flat with no Dex mod. I have a shield (which gives a +2 bonus), so I think total is either 22 or 24.

Is my AC calculation correct? If not, how should I be calculating my AC?

  • 9
    \$\begingroup\$ How did get to 22 and 24 exactly ? How much is your dex ? \$\endgroup\$
    – zakinster
    Commented Dec 10, 2019 at 7:44
  • 7
    \$\begingroup\$ I'm guessing that he mistakenly calculated it as 17 (tortle) + 3 (sorceror) + 2 (shield) + 2 (dex). \$\endgroup\$
    – nick012000
    Commented Dec 10, 2019 at 10:16

2 Answers 2


You must use one formula for calculating your AC

If your character happens to have multiple given formulas for calculating their armour class, due to their combination of racial traits, class features or equipment, you don't get to mash them all together. At any given time, you pick one basic formula and use that (ideally, choose whichever one gives you best AC).

As per the basic rules:

Some spells and class features give you a different way to calculate your AC. If you have multiple features that give you different ways to calculate your AC, you choose which one to use.

In your tortle's case, unless your dexterity bonus is better than a +4, there's no advantage to using the Draconic Bloodline feature to calculate your AC - it will be equal to or worse than 17, which is the default AC for the tortle. However, your shield offers a flat bonus to AC which is applied after figuring out your base AC, so you can always benefit from that no matter which basic AC formula you use. Assuming your dexterity modifier isn't that high, your tortle's AC should be 19.

You don't have to stick with the choice permanently - you can change which one you're using if it would be better for some reason. For instance, if your tortle received a buff which raised your dexterity score to 20 (or higher), the +5 modifier means it would now be better to calculate your AC using your bloodline feature, so you can decide to start using that instead - and of course you can use the old method again once the buff wears off and your dexterity drops. The game doesn't impose any conditions on when you can choose or change your choice, so you can recalculate your AC whenever it's relevant.

A useful way to interpret these rules might be that all of those formulas are actually always in effect, but they overlap, not stack. The final AC the character actually has at any given moment is simply determined by whichever formula produces the highest number, as the most powerful effect (assuming, of course, you want your character to have the best AC they can!)

  • 3
    \$\begingroup\$ A lore reason for why you can pick whichever at any point would be that as a Tortle you have natural armor which acts as a deterrent to damage. You have some dexterity to try to dodge attacks, but it doesn't help as much as just trying to use your shell to absorb the damage. In fact, if you focus on trying to dodge you're likely to slip up and expose yourself to damage (lower AC than your natural). But when you get a buff and are suddenly faster, you're now able to dodge more effectively than you can just take hits on your shell, so you just start dodging instead. \$\endgroup\$
    – IronSean
    Commented Dec 10, 2019 at 15:21
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    \$\begingroup\$ @IronSean: Mind you, that explanation doesn't really explain why tough draconic skin somehow only helps if you're fast. Are the tortles stripping off their shells to gain maneuverability, leaving the draconic skin underneath? Really, the point is that lore isn't primary here, balance is. Almost every game that allows layering armor either nerfs it, or is open to crazy layering exploits. D&D chose the former. \$\endgroup\$ Commented Dec 10, 2019 at 21:27

You choose which way you want to calculate it. You can take the 17 + 2 (from Tortle AC + shield) or you can pick 13 + DEX + 2 (from Draconic Sorcerer AC + shield).

The basic rules say

Some spells and class features give you a different way to calculate your AC. If you have multiple features that give you different ways to calculate your AC, you choose which one to use.

This means it's your choice which to pick.


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