There are two roulette wheels in common use and they pay exactly the same: 35 to 1 on a number, 17 to 1 on a split, even money on red. The only visible difference is that one has a single green 0 and the other has a 0 and a 00. That second pocket is worth a great deal to the house and nothing to you, and it is worth understanding exactly why.
The arithmetic of a single number
On a single-zero wheel there are 37 pockets. A bet on one number wins one time in 37 and pays 35 to 1. Over 37 spins at one chip each, you expect to lose 36 chips and win one bet worth 35 — plus your chip back, 36. Net: 37 out, 36 back. The house keeps 1 chip in 37, which is 2.70%.
On a double-zero wheel there are 38 pockets. The same bet wins one time in 38 and still pays 35 to 1. Over 38 spins: 38 out, 36 back. The house keeps 2 chips in 38, which is 5.26%.
Same payout, one extra way to lose. That is the whole trick: the odds got worse and the price stayed the same.
It is not just the straight-up bet
Every bet on the layout is priced as if the zeros did not exist. Red pays even money as though half the pockets were red; a dozen pays 2 to 1 as though a third of the pockets were in it. On both wheels every bet carries the same house edge as the single number — 2.70% on one, 5.26% on the other — because the zeros are the only thing making any of them unfair, as laid out in why every roulette bet has the same house edge. Add a zero and every bet gets worse by the same amount.
What 2.6 percentage points looks like
Small numbers are easy to wave away, so translate. Play 200 spins at 10 chips a spin — an unremarkable evening. On a single-zero wheel the expected loss is 54 chips. On a double-zero wheel it is 105. Same bets, same luck, nearly double the drift, from one pocket.
Which wheel is which
Single zero is the European wheel, standard across Europe, Asia and most online rooms. Double zero is the American wheel, standard in the United States and increasingly offered elsewhere because it earns more. Some American tables now add a triple zero, taking the edge past 7.6%. Payouts, again, unchanged.
Our wheel has one zero and thirty-seven pockets, in the standard European order — the sequence is in how roulette works. Play chips only, so the percentage is a matter of honesty rather than money; but it is the honest wheel.
The one rule that helps
Some single-zero tables soften the zero further with la partage or en prison: an even-money bet loses only half, or is held for the next spin, when zero comes up. That halves the edge on those bets to 1.35%. It is a rule to look for on a real table, and a reason a wheel's zero count is only the first question to ask about it.
