The real answer here is say No and scare the party.
I love doing this.
“Oh, right, you have that plus-one from that amulet. So twenty-eight. Yeah, that does hit.”
(Monster AC is actually 14, but I’ll let them sweat for a round or two anyway.)
Laughs in Mage Armor, Shield, Cat’s Grace, Reduce Person, and Protection from Evil… but still yes.
The cool thing about PF2e is that this can still be a relevant question, because that roll may or may not be a crit, and the answer tells you something important.
It also may or may not be a hit. A Vampire Guardian is a Level 10 creature and has an AC of 29.
Ah, but that’s why they’re flanking! The Vampire Guardian is off-guard (I think that’s the new terminology? I’m still trying to get used it it) and has a -2 penalty to his AC!
I tend to always ask so the Bard at least has a chance to use Cutting Words. Same goes for Light Domain Clerics.
And time wizards, or silvery barbs, or whatever other interrupts and reactions the party may have in their back pocket :)
I get this question from players, and it drives me just as nuts.
The joys of making a homebrew class and telling your playtester to try and break it as much as possible (Including any magic items he wants, to be fair) so that you know what to buff and nerf and otherwise adjust is that I actually do have to ask him if a 28 hits, because thanks to his build… it doesn’t always do that (Has between 22 and 33AC).
Probably not just a hit but a crit as well.
Thanks to UA warforged and generous magic item allowances (a staff of power and +2 shield I think were the relevant ones for AC) I had a wizard with 28 resting AC (33 with shield).
“[lie] Nope!”
Roll Deception.