Double ball roulette spins two balls at once, and the calculator above works out what that does to the odds. A straight-up number has a 5.26% chance that exactly one ball lands on it and a 0.073% chance that both do. On the usual pay table that’s 17 to 1 for one ball and 35 to 1 for both, which keeps the house edge at 2.70% on a single-zero wheel. The free calculator handles every bet and lets you type in your own table’s payouts.
Double ball roulette odds for every bet
Each ball is a separate spin, and both can finish in the same pocket. For a bet covering k numbers on a 37-pocket wheel:
Both balls win = (k/37)² Exactly one wins = 2 × (k/37) × (1 − k/37)
| Bet | One ball wins | Both win | Usual pay: one / both |
|---|---|---|---|
| Straight up (1 number) | 5.26% | 0.073% | 17 / 35 to 1 |
| Split (2) | 10.2% | 0.29% | 8 / 17 to 1 |
| Street (3) | 14.9% | 0.66% | 5 / 11 to 1 |
| Dozen (12) | 43.8% | 10.5% | 0.5 / 2 to 1 |
| Red or black (18) | 49.9% | 23.7% | stake back / 1 to 1 |
The pattern: both balls pay the normal roulette price, one ball pays half the profit minus half a unit. Any table using that rule has the same 2.70% edge as normal European roulette. If your table pays more for one ball, it pays less somewhere else, so put its numbers in under “Enter my table’s payouts”.
The both-balls special bet
Many double ball tables offer a bet that both balls land on one number you choose, at around 1,300 to 1. The chance is 1 in 1,369, so 1,300 to 1 carries a 4.97% house edge, nearly double the main game. Higher payouts on some tables bring it down; the calculator works it out for any price.
Two balls don’t change the long-run cost of roulette, only the shape of the wins. To check a normal wheel, the roulette calculator covers every bet, and the roulette system tester runs any betting pattern over 5,000 sessions.
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