Roulette: Rules, Payouts and the House Edge

Updated: 10 November 2026

Roulette is one of the oldest casino games. Online, you find it as a computer game run by a random number generator (RNG) and as live roulette with a real dealer on video. The rules are simple and the maths is completely open. This page explains the two wheels, the bets and payouts, the house edge, and why systems such as the Martingale cannot beat the game.

How roulette works

The wheel has numbered pockets. Numbers 1 to 36 are red or black, and the zero (0) is green. You place chips on the betting layout, the wheel is spun, and the ball stops in one pocket. Bets that cover that number are paid. All other bets lose.

European and American roulette

• European roulette: 37 pockets, numbers 1 to 36 plus one zero (0).
• American roulette: 38 pockets, numbers 1 to 36 plus a zero (0) and a double zero (00).

Both wheels pay the same amounts for the same bets. The extra 00 pocket on the American wheel adds one more way to lose without adding anything to the payouts. That is why the American wheel costs you about twice as much on average.

The game name or information screen tells you which wheel you are playing on.

Bet types and payouts

Bet	Numbers covered	Payout
Straight (one number)	1	35:1
Split (two numbers next to each other)	2	17:1
Street (a row of three)	3	11:1
Corner (a block of four)	4	8:1
Six line (two rows)	6	5:1
Dozen (1 to 12, 13 to 24, 25 to 36)	12	2:1
Column	12	2:1
Red or black, odd or even, 1 to 18 or 19 to 36	18	1:1

A payout of 35:1 means a winning KSh 100 bet on one number earns KSh 3,500, and your KSh 100 stake comes back as well, so KSh 3,600 returns to your balance. A payout of 1:1 means a winning KSh 100 bet on red earns KSh 100, so KSh 200 returns to your balance.

When the ball lands on zero, outside bets such as red, black, odd or even lose on most tables. Some tables have special rules for this case; they are listed in the game rules.

The house edge: the calculation

The house edge comes from the zero. The payouts are set as if the wheel had only 36 numbers, but it has 37 or 38 pockets.

European roulette (37 pockets). Imagine you bet KSh 100 on one number for 37 spins, and every number comes up exactly once. You have staked KSh 3,700 in total. You win once, and that win returns KSh 3,600. You are KSh 100 short out of KSh 3,700. That is 1/37, a house edge of 2.70%. The return to player (RTP) is 97.30%.

American roulette (38 pockets). Over 38 spins of KSh 100, you stake KSh 3,800. You win once and get back KSh 3,600. You are KSh 200 short out of KSh 3,800. That is 2/38, a house edge of 5.26%. The RTP is 94.74%.

This is an average over many spins, not what happens in any one session. In 37 real spins your number may come up three times, or not at all. The longer you play, the closer your results tend to move towards that average.

Why the bet type does not change the edge

The same calculation works for outside bets. On a European wheel, in 37 spins red comes up 18 times on average. Betting KSh 100 on red each time, you win KSh 100 eighteen times (KSh 1,800) and lose KSh 100 nineteen times (KSh 1,900). You are KSh 100 down out of KSh 3,700: again 1/37, or 2.70%.

So on a European wheel every standard bet has the same house edge. Choosing red instead of a single number changes how often you win and how much each win pays. It does not change the average cost.

On the American wheel almost every bet has the same 5.26% edge. One exception is worse: the five-number bet on 0, 00, 1, 2 and 3, which pays 6:1. Over 38 spins of KSh 100 (KSh 3,800 staked), it wins five times and returns KSh 700 each time, KSh 3,500 in total. The shortfall is KSh 300 out of KSh 3,800, a house edge of about 7.89%.

If you choose to play, a European wheel costs less on average than an American one. For more on RTP and house edge in other games, read RTP explained.

Why the Martingale does not work

The Martingale is a betting system for even-money bets such as red or black. You double your bet after every loss. The idea is that one win will cover all the losses and leave a small profit. Here is how it looks with a starting bet of KSh 100 on red:

Bet number	Stake	Total lost if this bet also loses
1	KSh 100	KSh 100
2	KSh 200	KSh 300
3	KSh 400	KSh 700
4	KSh 800	KSh 1,500
5	KSh 1,600	KSh 3,100
6	KSh 3,200	KSh 6,300
7	KSh 6,400	KSh 12,700

If any of these bets wins, your profit for the whole run is only KSh 100. If all seven lose, you are KSh 12,700 down, and the next bet would have to be KSh 12,800.

On a European wheel, the chance of red losing seven times in a row is (19/37) multiplied by itself seven times, about 0.94%. That looks small. But if you play 100 runs like this, the chance that at least one of them hits seven losses in a row is about 61%. One such loss of KSh 12,700 wipes out the KSh 100 profit from 127 successful runs.

Table limits make it worse. Every table has a maximum bet. Suppose, as an example, that a table’s maximum is KSh 10,000. After six losses in a row you would need to bet KSh 6,400, which is allowed; after seven you would need KSh 12,800, which is not. At that point the system stops, and the losses stay.

The Martingale does not change the house edge on any single spin. It only changes the pattern of results: many small wins, and now and then one very large loss.

Other systems and “hot numbers”

Other systems, such as the D’Alembert, the Fibonacci or following “overdue” numbers, only change the size or order of your bets. None of them changes the payouts or the pockets, so none changes the house edge.

The wheel has no memory. If black has come up eight times in a row, red is not “due” on the next spin. The chance is the same as on every other spin: 18 out of 37 on a European wheel. Believing otherwise is called the gambler’s fallacy, and it leads players to raise their bets at the worst moment.

RNG roulette and live roulette

In RNG roulette a computer program produces the result; in live roulette a dealer spins a real wheel on video. With the same wheel type, the payouts and the house edge are the same. Read more in live casino.

Before you play anywhere, check the operator’s GRA licence. The Gambling Regulatory Authority published its list of online licensed operators on 3 November 2026. Our guide to licensed casinos in Kenya shows the list and how to check a licence yourself.

Frequently asked questions

What is the difference between European and American roulette? European roulette has one zero and 37 pockets; American roulette has 0 and 00 and 38 pockets. The payouts are the same, but the extra 00 pocket raises the house edge from 2.70% on the European wheel to 5.26% on the American wheel.

Can the Martingale guarantee a win? No. It gives many small wins and now and then a very large loss.

Play responsibly