Roulette looks like the simplest game on the floor — a wheel spins, a ball drops, a number comes up — but the bets on the felt carry meaningfully different odds. It doesn’t require strategy, but understanding the math changes which version of the game is worth choosing.
European vs. American Wheels
The single most important roulette decision happens before betting: which wheel you’re playing. A European wheel has the numbers 1 through 36 plus a single zero (37 pockets); an American wheel adds a second zero (38 pockets). The extra pocket doesn’t change payouts but pushes the house edge from 2.7% (European) to 5.26% (American) — nearly double.
Because the difference is purely structural, choosing European (or French) over American whenever available is one of the simplest, highest-impact decisions a player can make.
Inside and Outside Bets
Roulette bets split into inside and outside bets:
- Inside bets sit directly on individual numbers or small groups — straight-up singles, splits (two), streets (three), corners (four), lines (six) — paying more because they’re less likely to hit.
- Outside bets cover broader categories — red/black, odd/even, high/low (1–18 or 19–36), columns, dozens — paying less because they’re more likely to hit.
Neither category carries a better house edge on a European wheel — every bet carries the same 2.7% edge, since payouts match true odds minus the zero’s share. The difference is variance: inside bets are rare, larger wins; outside bets are frequent and smaller.
Payouts, Odds and the House Edge Math
| Bet Type | Example | Payout | Winning Numbers (European) |
|---|---|---|---|
| Straight Up | Single number | 35:1 | 1 of 37 |
| Split | Two adjacent numbers | 17:1 | 2 of 37 |
| Street | Row of three numbers | 11:1 | 3 of 37 |
| Corner | Block of four numbers | 8:1 | 4 of 37 |
| Line | Two adjacent rows (six numbers) | 5:1 | 6 of 37 |
| Dozen / Column | 12 numbers | 2:1 | 12 of 37 |
| Red/Black, Odd/Even, High/Low | 18 numbers | 1:1 | 18 of 37 |
Run the math on any row and the house edge comes out the same 2.7% on a European wheel — the payout is always slightly short of true odds because of the zero.
See These Bets on the Actual Layout
Rather than picture it, here’s the real European (single-zero) table. Pick a bet type below and watch which numbers it actually covers.
La Partage, En Prison and Other Edge-Reducing Rules
Some European and French variants add rules that soften the zero’s impact on even-money outside bets (red/black, odd/even, high/low):
- La Partage: if zero comes up, half of any losing even-money bet is returned instead of the whole bet being lost.
- En Prison: instead of losing half, the bet is “imprisoned” for one more spin — if it wins, the stake is returned with no extra winnings.
Either rule roughly halves the house edge on those bets, to around 1.35% — among the best odds anywhere in the casino for that bet category. Neither applies to inside bets or American wheels.
Playing Roulette Online
Online roulette comes as RNG-based digital wheels or live dealer roulette, streaming a real wheel and ball. The math is a property of the wheel and bet, not the format — a European wheel carries the same 2.7% edge either way. Some platforms default to American wheels or blend both, so confirm which type you’re playing; on any licensed Ontario casino, the wheel type must be clearly labelled.
For how roulette’s edge compares to other games, see how RTP and house edge work; the casino guide covers confirming licensing. Play roulette as entertainment within a budget set in advance — the responsible gambling page has tools to help.