Dice & Craps Probability Lab
Two dice, 36 equally likely outcomes, and every craps bet priced off that one fact. Roll as many times as you like and watch randomness settle into math.
Roll the dice.
Observed totals vs. exact probability
Green bars = your rolls. Gold line = the exact expectation.
Pass Line simulator
Come-out roll: 7 or 11 wins, 2, 3 or 12 loses, anything else becomes the point — then the point must repeat before a 7.
All 36 outcomes
| Total | Ways | Probability | Odds against |
|---|
Craps bets, best to worst
| Bet | House edge |
|---|---|
| Free odds (behind Pass/Come) | 0% |
| Don't Pass / Don't Come | 1.36% |
| Pass / Come | 1.41% |
| Place 6 or 8 | 1.52% |
| Field (12 pays 3:1) | 2.78% |
| Place 5 or 9 | 4.00% |
| Field (2 & 12 pay 2:1) | 5.56% |
| Place 4 or 10 | 6.67% |
| Big 6 / Big 8, Hard 6 / 8 | 9.09% |
| Hard 4 / 10, Any Craps, Yo (15:1) | 11.11% |
| Aces or Twelve (30:1) | 13.89% |
| Any Seven | 16.67% |
Why 7 rules the table
There are six ways to make 7 (1-6, 2-5, 3-4, 4-3, 5-2, 6-1) and only one way to make 2 or 12. That single asymmetry decides every payout on a craps layout. The Pass Line wins 244 of every 495 games on average — 49.29% — which is where its 1.41% edge comes from.
Roll 10,000 times and the bars hug the gold line. Roll 30 times and they don't — and that short-run noise is what makes people believe in hot and cold dice. See also the Coin-Flip Streak Lab and The Law of Large Numbers.