I like to make system-neutral stuff. I don’t particularly like writing “AC 8 (12)” or “AC 12 (8)” or “AC: as leather armor”. Here’s my proposal for a terse way to write any-edition Armor Class: **Just write the AC bonus.** Thus:

AC: +6

I think it’s pretty intuitive that this guy’s AC is 16 in 3e (counting up from 10), AC 4 in 1e (counting down from 10), and AC 3 in Basic (counting down from 9).

This system doesn’t collide with any other notation. “AC: -6” has meaning in other systems but “AC: +6” doesn’t.

It also works within the expectations of each edition.

Monster publishers: if you like it, start using it. If it needs a name, I suggest “Unified AC Notation” and you can link to this page.

Dang, that is so obvious in hindsight. Will do.

Brilliant!

hey, that’s brilliant!

Chain + Shield is AC 4 in AD&D as well as OD&D and Basic. Adding +6 to AC 9 won’t be correct.

@hedge: I suspect the system is used primarily for non-armor-wearing monsters, but I agree there are some that do, such as bandits etc. I guess whoever is running a system with base AC 9 just needs to imagine that the actual base AC is truly 10 but an unarmored person has +1 AC equivalent “armor” in the form of his skin or something.

Really, it should be ±6, just saying.

@hedgehobbit – good point, apart from the very lowest ACs, monster and armor AC are the same in Basic and 0e, so you might as well always subtract from 10.

@Canageek: 1e is not consistent here. You have magic armor +1 which subtracts from AC, but a Dexterity defensive adjustment of -1 which also subtracts from AC. + and +/- are both potentially correct, but I’ll stick with + because I think it’s a little more intuitive.