Chapter 1 of 6 · 1 min read
How Armor Works
AC, DR and critical hits in one page.
Armor Class (AC)#
AC shows how easy (or hard) it is to land a hit when you attack with a weapon, fist, arrow, etc. Everyone starts at 10. Only shields, Dexterity ability bonus, magic items, or magic can raise or lower it.
Armor does not change AC. Even a knight in full plate can still be struck - AC is about whether the attack connects, while armor itself provides Damage Reduction: DR.
A shield gives +2 to AC.
Damage Reduction (DR)#
Armor protects by reducing damage once a hit lands. Each type of armor has a flat DR value that is subtracted from the physical damage taken.
Creatures, monsters, etc. may have a physical or magical component that raises their DR naturally.
Shields do not have DR and do not reduce damage. Shield raises AC, making it harder to hit you. A natural 20 ignores DR completely.
Critical Hits#
A critical hit occurs when you roll a natural 20 on a 1d20 with melee weapons. It's an automatic hit, ignores DR and is two times (x 2) damage.