Roulette is one of the most recognisable games found in online and land-based casinos, yet many are unaware of how the odds and return to player (RTP) work behind the scenes. Knowing what these terms mean is key to making informed choices at the table.
This guide explains how RTP relates to roulette, the odds for common bets, and how variations like European and American wheels affect the numbers you see.
You will find clear examples showing how RTP is worked out, a look at whether betting systems can influence outcomes, and practical guidance on using RTP information to help manage your bankroll with care.
What Is RTP In Roulette?
Return to Player, known as RTP, is a percentage figure that describes the average long-term payout rate of a game. In roulette, RTP represents the portion of all wagered money that may be paid back to players over a very large number of spins.
For example, if a roulette game has an RTP of 97.3%, this means that for every £100 wagered, the game is designed to pay out £97.30 over time. The remaining £2.70 goes to the casino as profit. RTP is a theoretical calculation based on millions of spins; it is not a prediction for any short session.
Results for individual sessions can be very different from the stated figure. Each spin is independent, and strategies cannot change the underlying probabilities. RTP should be treated as a guide, and play should only take place within a set budget.
With that in mind, it helps to understand how the odds that drive RTP are calculated.
How Are Roulette Odds Calculated?
Roulette odds are calculated from the number of possible outcomes on the wheel. Each pocket, including zero (and double zero on American wheels), represents one outcome.
To find the chance of a particular bet, compare the number of winning pockets it covers with the total number of pockets. A single-number bet on a European wheel covers 1 of 37 outcomes, while the same bet on an American wheel covers 1 of 38.
Bets that cover more numbers, like red or black, land more often per spin but pay less than a single-number bet. As noted earlier, each spin is independent, so previous results do not influence the next one.
Wheel layouts change these numbers, which is why European and American versions produce different house edges.
European Vs American Roulette House Edge
The house edge shows the percentage of each wager the casino may keep, on average, over time, and it depends on the wheel.
European roulette has one single zero among 37 pockets. The house edge is about 2.7%, which corresponds to an RTP of roughly 97.3%.
American roulette has 38 pockets, including both single zero and double zero. The extra pocket raises the house edge to around 5.26%, giving an RTP near 94.74%.
The difference comes from the added double zero on the American wheel, which increases the number of non-paying outcomes. With the wheel choice clear, the next step is to see how common bets compare.
Common Bets And Their Probabilities
Roulette offers several betting options, each with its own probability of winning. Understanding these helps set expectations before placing a wager.
Straight Up (Single Number)
A straight up bet is placed on a single number. On a European wheel, there is 1 winning number out of 37 possible outcomes, giving a probability of about 2.7%. On an American wheel, it is 1 out of 38, or about 2.6%.
The payout for this bet is usually 35 to 1, so a successful £1 bet might return £36 in total (£35 profit plus the original stake).
Split And Street Bets
A split bet covers two numbers next to each other on the table. In European roulette, this means 2 chances out of 37 (about 5.4%), and in American roulette, 2 out of 38 (about 5.3%). The payout is usually 17 to 1.
A street bet covers three numbers in a row on the table. This gives 3 chances out of 37 (roughly 8.1%) on a European wheel or 3 out of 38 (about 7.9%) on an American wheel. The payout for a street bet is typically 11 to 1.
Column And Dozen Bets
Column and dozen bets each cover 12 different numbers. In European roulette, this is 12 out of 37, which is about a 32.4% chance of winning. For American roulette, it is 12 out of 38, or about 31.6%. The payout is generally 2 to 1.
Red Or Black, Odd Or Even
These even money bets cover 18 numbers each, such as all the red pockets or all the black pockets. In European roulette, there are 18 out of 37 possible outcomes (around 48.6%). For American roulette, it is 18 out of 38, or about 47.4%.
These bets offer the highest chance of any standard bet but do not win on every spin because of the zero pockets. With the basics in place, table rules are the next piece that can shift how returns add up over time.
How Table Rules Affect RTP
Different roulette tables may use rules that slightly adjust how the game plays, and those rules can change RTP for some bets.
Some European tables offer La Partage or En Prison on even-money bets. With La Partage, if the ball lands on zero, players lose only half their even-money stake instead of the full amount. En Prison holds the stake for the next spin in the same situation. Both reduce the house edge on even-money bets from about 2.7% to around 1.35%, improving RTP on those bets from roughly 97.3% to about 98.65%.
American tables usually do not offer these features, and the extra double zero already raises the house edge. Checking the table rules before playing helps you understand what might happen to even-money bets when zero appears.
To see how these ideas work in practice, it helps to run through a few simple calculations.
Example RTP Calculations For Typical Bets
RTP for roulette bets is derived from how often a bet could win and what it pays over many spins.
For a single number bet on a European wheel, the chance of winning is 1 in 37. If £1 is placed on the same number over 37 spins, the theoretical return is one win paying £36 and 36 losing spins at £1 each. The total staked is £37, the total returned is £36, so the RTP is £36/£37, or about 97.3%.
For an even-money bet, such as red or black on a European table, the underlying maths gives a similar overall RTP of around 97.3% across many spins. Where La Partage applies, the effective RTP on even-money bets improves to about 98.65% because only half the stake is lost when zero lands.
On American wheels, the extra double zero reduces RTP across standard bets to about 94.74%. One notable exception is the American five-number bet covering 0, 00, 1, 2, and 3, which carries a higher house edge of about 7.89% and an RTP near 92.11%.
Given the fixed payouts and probabilities, it is natural to ask whether changing stake size or order can move these figures.
Can Betting Systems Change Roulette RTP?
Betting systems, such as Martingale or Fibonacci, adjust stake size after wins or losses according to a pattern. While they may alter how a session feels, they do not change the RTP of roulette, which is set by the wheel layout and payouts.
Each spin is independent, so past results do not influence the next outcome. Progressive systems can also increase exposure quickly, leading to larger losses if a sequence goes against the player. If used at all, they should only be applied with funds set aside for that purpose.
So how can RTP be useful in practice? It is most helpful when setting a budget and pace for play.
How To Use RTP Information When Managing Your Bankroll
Understanding the RTP of roulette can help with setting expectations and deciding how to manage a budget. Because RTP reflects long-term outcomes, it should guide planning rather than be treated as a prediction for any single session.
If a player chooses to play, knowing the RTP can help them decide on comfortable stake sizes, session length, and the total amount they are prepared to spend. Higher RTPs suggest a larger proportion of stakes may be returned on average, though short-term results can vary.
Set personal limits that suit your circumstances, take regular breaks, and never wager more than you are willing to lose. If gambling starts to affect your well-being or your finances, seek support early. Independent organisations such as GamCare and GambleAware offer free, confidential help for anyone who needs it.
Understanding how odds and RTP work makes it easier to make informed choices if you decide to play, and to keep control of how much you spend.
**The information provided in this blog is intended for educational purposes and should not be construed as betting advice or a guarantee of success. Always gamble responsibly.