From BRWiki
 D20
|
This article is a D20 reference page
The System Reference Document is a comprehensive toolbox consisting of rules, races, classes, feats, skills, various systems, spells, magic items, and monsters compatible with the d20 System version of Dungeons & Dragons and various other roleplaying games from Wizards of the Coast.
|  D20
|
Attack Roll
An attack roll represents your attempt to strike your opponent on your turn in a round. When you make an attack roll, you roll a d20 and add your attack bonus. (Other modifiers may also apply to this roll.) If your result equals or beats the target’s Armor Class, you hit and deal damage.
Automatic Misses and Hits
A natural 1 (the d20 comes up 1) on an attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. A natural 20 is also a threat—a possible critical hit.
Back to System Reference Document -> Combat Rules -> Combat Statistics