What does an hour on a slot machine cost?
How do stake, session length, speed and RTP add up? Work out the theoretical expected loss without mistaking it for a prediction.
The slot cost calculator shows how much you stake in total under your assumptions and what net loss is mathematically expected. It does not predict how a single session ends. The figures are a model for adults, not a recommendation to play.
The four inputs
- Stake per spin: a fixed amount in pounds.
- RTP: the theoretical return to player of the game, in per cent.
- Session length: the assumed time in minutes.
- Seconds per spin: the assumed time between games.
In Great Britain an online slot spin must last at least 2.5 seconds, so the calculator uses that as its lower limit. The Gambling Commission's stake limit guidance also sets a maximum stake per spin for online slots of £5, or £2 for players aged 18 to 24. Germany has a minimum of 5 seconds per spin; other markets have their own rules.
Example: one hour at £0.50 a spin
At 60 minutes and 10 seconds per spin you get 360 spins. At £0.50 a spin that is £180 staked in total. With an assumed RTP of 96 per cent, the expected loss is £180 × (1 − 0.96) = £7.20.
"Total staked" is the sum of all stakes, including any winnings played again. It is not the same as a deposit. Whether you actually reach that number of spins also depends on having enough balance.
Limits of the result
The calculator assumes constant values and rounds the number of complete spins down. It does not account for breaks, changes of stake, fees or stopping early. The spread of possible wins and losses is missing as well, so it cannot tell you how likely you are to play through an hour with a given budget.
What the average does and does not say is explained in What does RTP mean?. If gambling is getting hard to control, see Responsible gambling. The calculators overview has more maths tools.