What is RTP in online casinos?

RTP, or Return to Player, indicates the average proportion of stakes that a casino game pays back to players over the long term. 

A simple figure, but one that is often misunderstood

In the world of online casinos, certain terms directly influence how you choose a game. RTP, or return to player, is one of them. It is the theoretical percentage of bets that a game pays back to players over time.

If a slot machine has an RTP of 96%, this means that, on average, over a very long period, the game pays out €96 for every €100 wagered. The remaining €4 represents the casino’s statistical advantage, often referred to as the house edge.

But be careful! An RTP of 96% does not mean that a player will automatically get back €96 after betting €100. Nor does it guarantee that a short session will end with a limited loss. The RTP is an average calculated over a very large number of games.

How RTP is calculated

The calculation of the RTP is based on a formula that appears simple. It is obtained by dividing the total winnings paid out to players by the total amount wagered, and then expressing the result as a percentage. Let’s imagine a slot machine that has received €1 million in wagers over its lifetime and has paid out €950,000 in winnings. Its RTP would then be 95%. 

However, the simplicity of the formula should not obscure the complexity of the actual calculation. Game developers and casinos rely on simulations, algorithms and a vast amount of data to establish these percentages. The aim is to verify that the game does indeed match the expected payout rates.

Online casinos and land-based casinos: why the rates differ

The RTP can vary depending on the type of establishment. Online casinos generally offer higher return-to-player rates than land-based casinos. The main reason lies in operating costs.

An online casino does not have the same overheads as a land-based establishment. It does not need to maintain a large gaming hall, manage as many staff on site, or bear the same building-related costs. This leaner structure often allows them to offer games with a more favourable RTP.

Online casinos generally offer payout rates of between 92% and 98%. Land-based casinos, on the other hand, often have lower RTPs, typically ranging from 80% to 90%.

Land-based casinos must also comply with an hourly loss rate set by the Gaming Commission. This is a legal indicator that estimates how much a player can lose on average in an hour, taking into account the stake, playing time and payout rate. It varies depending on the type of establishment: C-licensed bingo halls in cafés have an average loss of €12.50 per hour, B-licensed slot machine halls rise to €25, whilst A-licensed casinos can reach €70 per hour, calculated on the basis of millions of simulated games.

Not all games are created equal

The RTP also varies significantly depending on the type of game. Certain categories are known to offer higher rates, especially when the rules are well understood and the player employs a suitable strategy.

European roulette is often cited as one of the games favoured for its favourable rate. Thanks to its single zero pocket, it offers an RTP of around 97.3%. American roulette, which has a single zero and a double zero, has a lower rate, around 94%.

Blackjack can offer an even higher RTP, frequently exceeding 99% when basic strategy is applied correctly. Players must know the rules, understand the odds and make the right decisions based on their hand and the dealer’s upcard.

Legal limits on RTP in Belgium

In Belgium, the RTP of legal online casino games is subject to strict regulation. Unlike in some foreign markets where operators can choose less generous versions of the same game to maintain their margins, casinos holding a Belgian licence cannot freely alter the payout rate.

A game’s RTP is approved as part of the Belgian licence and then certified in advance by independent audit laboratories. Once validated, this rate is technically locked: the operator does not have access to the game’s source code and therefore cannot discreetly reduce the return-to-player percentage.

This rule protects players from variable ‘RTP tiers’, where the same game may be offered with different payout profiles depending on the market or casino. This approach makes Belgium a more protective market in terms of transparency and mathematical fairness.

Key points to remember before betting

The RTP is one of the most useful indicators for understanding an online casino game. It represents the average percentage of stakes paid back to players over a very long period. The higher it is, the more statistically generous the game is. However, this figure remains an average, not a certainty.

Online casinos often offer higher RTPs than land-based casinos, mainly due to lower operating costs. Game variants also play a decisive role: European roulette can be more advantageous than American roulette, and blackjack can offer a very high return when basic strategy is applied correctly.

Ultimately, the RTP is simply a benchmark to help you compare, choose and understand better.