Noob AC question

[Noonien]

Hi all,

I have a problem with AC regarding on of the characters in my group.
For all it seems AC is calculated correctly, but for our Rogue I dont understand it.
He wears a lether armor: AC 11.
He is proficient in light armor.
He has no dex bonus (+0).

From my understanding his AC should be : 11(base) + 2 (prof) +0 Dex bonus = 13
But he only has AC 11.

For all other classes it works that the AC prof bonus is added correctly.
Sure, I could chnage this manual, but am I really right or do I calculate it wrong ?

Btw additional question: Why does FGU always calculate with AC 10 as base and then add the rest value of the AC? For example half plate is base 10 + 5 .

[Zacchaeus]

Your armour class is base 10 + the bonus given by the armour you are wearing + dex bonus if appropriate.

So for leather armour your AC is 10 + 1 = 11 + any dex bonus. (And if you have a rogue without any dex bonus then the party are in deep trouble). You don't add your proficiency bonus to your AC.

If you are not proficient with the armour you are wearing you have disadvantage on ability checks, attacks and saving throws that involve Strength or dexterity and cannot cast spells.

Fantasy Grounds uses a base AC of 10 because that's how armour class is calculated if you don't wear any armour.

Note also that FG calculates AC automatically when you equip or unequip armour. If other players are getting an addition to their AC for proficiency; then they have manually interfered with this calculation.

[Noonien]

Hi Zacchaeus !

Thanks a lot, I checked it again and you are right, the others also dont get prof bonus for AC, their bonus comes from DEX or CON.
Didnt know this, thought prof for an armor type means you get +2, understood now that this is wrong and the benefit of armor prof is to not have disadvantage.
So all understood now, topic is solved :)

[GavinRuneblade]

Hi Zacchaeus !

Thanks a lot, I checked it again and you are right, the others also dont get prof bonus for AC, their bonus comes from DEX or CON.
Didnt know this, thought prof for an armor type means you get +2, understood now that this is wrong and the benefit of armor prof is to not have disadvantage.
So all understood now, topic is solved :)

Only the three Warforged Subraces from Wayfinder's Guide to Eberron actually add proficiency to AC. The new warforged race from Rising from the Last War removed this.