Roulette House Edge
The roulette house edge is the long-run mathematical advantage the casino has on every bet. It is fixed by the wheel layout and the payout structure - not by the bet type, not by the player, and not by any strategy you layer on top.
This is the single most important number in roulette. Knowing it makes every system on the market easy to evaluate.
The three standard numbers
| Wheel | House edge on standard bets | House edge on even-money with La Partage |
|---|---|---|
| European (single zero) | 2.70% | n/a |
| American (zero & double zero) | 5.26% | n/a |
| French (single zero) | 2.70% | 1.35% |
Where the 2.70% comes from
European has 37 pockets. A straight-up bet covers 1 pocket and pays 35:1. Fair payout would be 36:1 (the bet should win once for every 36 losses on average). The casino keeps the 1-unit gap.
1 unit / 37 pockets = 2.7027% on every dollar wagered. Every bet on the wheel - splits, dozens, red, black, 1-18 - has the same percentage edge because the payouts and probabilities scale identically.
Where the 5.26% comes from
American has 38 pockets. Same straight-up bet pays 35:1. Fair would be 37:1. The gap is 2 units instead of 1.
2 units / 38 pockets = 5.263% on every dollar wagered. Almost exactly double the European edge.
Where the 1.35% comes from
French roulette uses the European wheel but adds La Partage on 1:1 bets: when zero hits, you lose only half your stake.
Standard European 1:1 expected loss per dollar = 1/37 = 2.70%. With La Partage, half the stake is returned on zero, so expected loss = 0.5/37 = 1.35%.
La Partage only applies to even-money bets (red, black, odd, even, low, high). Other bet types on French roulette keep the 2.70% edge.
Why systems do not change the edge
The house edge is a property of the wheel and the payouts. A betting system changes which spins are big and which are small, but the percentage applied per dollar wagered is identical.
Across a session of total wagered W, expected loss is W × edge. Martingale often makes W very large (lots of double-up bets), which makes the absolute expected loss large. Flat betting minimises W and therefore minimises absolute expected loss.
The percentage edge stays the same. There is no system that escapes it. See Can you beat roulette with a strategy.
House edge per bet type (American five-number trap)
On American roulette, almost every bet has 5.26% house edge. The exception is the five-number bet covering 0, 00, 1, 2, 3, which has 7.89% edge.
There is no 'good' bet on American roulette, but the five-number bet is the worst.
Practical implications
- If you have a choice, play European or French.
- Avoid the American five-number bet entirely.
- Minimise total wagered if your goal is preserving bankroll.
- Strategy choice does not change percentage edge, only the shape of variance.