Roll a D20 Online

Instantly roll a D20 (20-sided die) online! Perfect for D&D, Pathfinder, and tabletop RPGs—no downloads, no ads. Start your next adventure now.

A d20 shows a number from 1–20 with equal probability. It’s the workhorse die in tabletop RPGs like D&D: used for attack rolls, saving throws, and ability checks. The average (expected) result of a fair d20 is 10.5.

Quick facts

  • Natural 20: a roll of 20 before modifiers. Commonly a critical hit on attacks.
  • Natural 1: often an automatic miss on attacks.
  • Advantage: roll 2d20 and keep the higher. Expected value ≈ 13.825.
  • Disadvantage: roll 2d20 and keep the lower. Expected value ≈ 7.175.
  • Chance of a natural 20: 5% (single roll), 9.75% (with advantage), 0.25% (with disadvantage).

D20 probabilities you'll actually use

These are the chances to meet or beat common target numbers on a d20.

Target (DC) Single d20 With Advantage With Disadvantage
≥ 580%96.00%64.00%
≥ 1055%79.75%30.25%
≥ 1245%69.75%20.25%
≥ 1530%51.00%9.00%
≥ 1815%27.75%2.25%
20 (Nat 20)5%9.75%0.25%