What Are RTP and House Edge? Formula, Difference, and a 99% RTP Example

Direct answer

RTP and house edge are two views of the same long-run expectation. They are not a promise for one session and cannot predict the next round.

Quick facts

Core formula

House Edge = 1 − RTP

99% RTP

1% House Edge

Best fit

Fixed-rule expectation models

Does not mean

One session should return RTP

01

What RTP means

RTP, or Return to Player, is the theoretical average share returned over a large number of repeated trials. A fixed-rule game with 99% RTP has a long-run expected return of 0.99 units per unit wagered.

That is an expectation, not a guarantee. A small sample of rounds can finish far above or below 99%.

02

How house edge is calculated

For a fixed-rule expectation model, House Edge = 1 − RTP. A 99% RTP corresponds to a 1% house edge; a 96% RTP corresponds to 4%.

Decision-dependent games or versioned paytables need more context because one headline percentage may not describe every strategy or configuration.

03

RTP, EV and variance are different

Expected value describes the average. Variance describes how widely outcomes spread around that average. Two games can both have 99% RTP and still feel radically different over short samples.

Low-hit, high-multiplier models generally create larger short-run swings, so RTP alone does not describe the full risk shape.

04

Why RTP does not make losses 'due' to reverse

Independent random trials do not compensate a session just because earlier results were below expectation. Long-run averages are statistical properties of many trials, not a debt owed to a particular player or session.

Treating a losing stretch as evidence that a win is now due confuses the law of large numbers with the gambler's fallacy.

EXAMPLE

Simple example

• Theoretical RTP = 0.99
• House Edge = 1 − 0.99 = 0.01 = 1%
• A sample of 100 independent rounds does not have to return exactly 99%; realized results can still deviate materially from expectation.

Frequently asked questions