Odds of rolling 21 on 2d20
Chance per roll
5.00%
20 of the 400 ways 2 20-sided dice land add up to 21 — about one roll in 20.0. Among the 39 totals 2d20 can make, that is the likeliest total.
Every total 2d20 can roll, with 21 picked out. The peak is 21 at 5.00%.
Exactly 21, or past it?
Plenty of games ask you to beat a number rather than hit it, and the two are not close.
| Exactly 21 | 5.00% |
| 21 or more | 52.50% |
| 21 or less | 52.50% |
The 20 ways to make it
Too many to list usefully — 20 ordered combinations out of 400. Ordered is the point: with two dice, 1 and 6 is a different outcome from 6 and 1, and counting them as one is the commonest way to get dice odds wrong.
Other rolls worth knowing
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