Pick a bet, a wheel and a stake. The numbers come from the game's published rules — no estimates involved.
Why the wheel type decides everything
Every roulette payout is set as if the wheel had 36 pockets: a single number pays 35:1, a dozen 2:1, red 1:1. The zeros are the house edge — pockets the payout table pretends do not exist. One zero makes the gap 2.70%; the American second zero doubles it to 5.26% for identical payouts.
Every standard bet on the same wheel carries the same edge. Inside bets pay more only because they hit less, in exact proportion — there is no combination of standard bets that changes the long-run number.
The practical rule this calculator makes visible: between two wheels with the same payout table, always sit at the one with fewer zeros. It is the only roulette decision that changes the maths.
Methodology
Probability is winning pockets over total pockets (37 European, 38 American). Expected value pays out the published ratio on a win and forfeits the stake on a loss; the house edge is the negative of that expectation as a share of the stake. Every figure derives from the same pocket counts, so they cannot disagree.