How RTP and house edge work

Return to player (RTP) is the average share of all stakes that a game pays back over a very large number of rounds. House edge is the remainder: 100% minus RTP. A game with a 96% RTP keeps, on average, KES 4 of every KES 100 wagered. It is an average, not a promise for one session.

By Nairobi Ultimate Editorial (prepared with AI tools under our editorial policy) · Last updated 2026-10-04

The two numbers are one number

Every casino game is a set of bets with fixed probabilities and fixed payouts. Multiply each possible payout by its probability, add the results, and you get the average amount returned per shilling staked. That average is the RTP, and it is the same idea as expected value written as a percentage.

House edge is what is left over. If a game returns 96 cents of every shilling on average, the remaining 4 cents is the operator's margin.

house edge (%) = 100% − RTP (%)

The margin is built into the paytable. It does not depend on who is playing, on the time of day or on how the previous rounds went.

What the percentage costs in shillings

The edge applies to the total amount wagered, not to the amount deposited. The table shows the expected cost for each KES 1,000 wagered at different percentages. The roulette rows are exact results of the wheel layout; the other rows are round figures chosen to show the scale.

The roulette arithmetic is set out in the guide to where the roulette edge comes from. For any other game, the figure that matters is the one displayed on the platform where the game is offered.

Why a deposit shrinks faster than the percentage suggests

A common misreading is "96% RTP means I keep 96% of my money". The percentage is charged on every bet, and players usually stake the same money many times.

The same effect can be seen by re-staking a whole balance. After one full cycle the average balance is 96% of the start; after ten cycles it is 0.96 multiplied by itself ten times, about 66%; after twenty cycles, about 44%. The more times money passes through the game, the larger the share the edge takes.

Long run and short run

RTP describes a very large number of rounds across all players. A single evening is a tiny sample, so results scatter widely around the average. How widely depends on the game's volatility: two games with the same RTP can behave very differently over a hundred rounds.

This scatter is why people leave a session ahead from time to time. It is also why a winning night says nothing about the game being generous, and a losing night says nothing about it being "due". Each round of a game of pure chance is independent of the last.

Over more and more rounds the scatter shrinks relative to the total wagered, and the average result closes in on the built-in percentage. The operator, which sits on the other side of every round from every player, is always playing the long run.

What Kenyan rules say about displaying it

The Gambling Control (Conduct of Gambling Operations) Regulations, 2026 say in regulation 20(2) that a licensee "shall display clearly rules of games, odds, house edge and average return to the player". Regulation 20(3) extends the casino games rule to online gambling activities "with the necessary modification, where applicable".

For online games, regulation 45(1) requires that the game rules are clearly displayed on the approved platform before a player places any wager. The same regulation states that the "theoretical return to player percentage for each game shall be publicly disclosed" on the licensee's online gambling platform or website.

Regulation 45(2) ties the percentage to testing: the random number generator used for games of chance is to be certified so as to statistically test "the randomness, theoretical return to player". How that works is covered in the guide to RNG testing and certification in Kenya.

How to read an RTP figure sensibly

• Look for the word "theoretical". The published figure is calculated from the game's rules. It is not a record of what the game paid last week.
• Check which bet it refers to. Some games carry several bets with different margins. A side bet can cost far more than the main bet on the same table.
• Read it where you play. Do not assume a figure seen elsewhere applies to the version in front of you. The rules screen of the game on the licensed platform is the reference.
• Convert it to a cost. Multiply the edge by your stake and by the number of rounds you expect to play. That is the average price of the session.

Speed matters as much as the percentage. A game that settles a round every few seconds pushes far more money through the edge per hour than a slow table, which is one reason crash games deserve a careful look.

What RTP does not tell you

It does not tell you how often you will win, how large the swings are, or how long a balance will last. It is silent on the largest prize and on how rare it is.

It also cannot be improved by bet sizing in a game of pure chance. Raising stakes after losses, lowering them after wins or switching between bets with the same margin leaves the average cost per shilling exactly where it was.

The honest summary is short. RTP below 100% means the game costs money on average, the cost grows with every shilling wagered, and the Act treats gambling as "the playing of a game of chance for prize winning" (section 2), not as a source of income.