Slots & Gaming Machines
Slot machine payouts
Slot machine payouts, or return-to-player (RTP), are the average percentage of all staked money a machine returns as prizes over a very large number of spins.
Key points
- RTP is an average over many plays, not a per-spin guarantee — a machine with 85% RTP will not return 85p per £1 in a single session1.
- Each spin is random and independent; the payout is set by the machine's programmed probabilities and prize schedule1.
Common questions
Can casinos control slot machine payouts?
How to calculate slot machine payouts?
Multiply each winning combination's probability by its payout, sum all results, and divide by the total stake per spin. For example, a traditional three-reel machine might yield a theoretical return of 94.545%.4
Where this term is used
Not the same as
- Slot machine — the physical or digital device, not the measure of its returns
Related terms
Slots
Slot machine
The physical or digital gambling device that uses reels and paylines.
Slots
Slot machine jackpot
The top prize on a slot machine, often progressive and linked across machines.
Slots
Slot machine reels
The spinning columns on a slot machine that display symbols.
Slots
Slot machine price
The cost to purchase a slot machine for a casino or private collection.
Slots
Casino slots
Slot machines found in a casino, including video slots and classic reel games.
Slots
Slot machine symbols list
A guide to common symbols on slot reels and their meanings.
Sources
- Return to player - how much gaming machines payout gamblingcommission.gov.uk Defines RTP as average proportion of stakes returned and explains it is not a per-spin guarantee.
- How can gaming machines meet their %RTP if they are ... gamblingcommission.gov.uk Explains how machines meet %RTP and the display requirement under section 240.
- Slots - Payback Percentages wizardofodds.com States Nevada slots minimum theoretical payback of 75%.
- How to Calculate the Return for a Slot Machine - Wizard of Odds wizardofodds.com Provides example calculation of 94.545% theoretical return for a three-reel machine.
Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.