The expected loss calculator turns a game’s RTP into money per hour. £1 spins, 500 an hour, on a 96% slot: that’s £500 through the machine every hour and an average loss of £20. It’s free, takes any currency, and shows the monthly and yearly figure once you add how often you play.
Expected loss calculator: the one formula
Everything here comes from a single line:
expected loss = bet × bets per hour × house edge
The house edge is 100% minus the RTP. A 96% RTP slot keeps 4p of every £1 you bet, on average, over a very long run. European roulette keeps 2.7p. Blackjack played well keeps about half a penny.
So why do slots feel so much more expensive than the 4% suggests? Speed. You aren’t betting £1 once. You’re betting it 500 times.
| Game | Bet | Per hour | Edge | Expected loss/hour |
|---|---|---|---|---|
| Online slot, autoplay | £1 | 500 spins | 4% | £20.00 |
| Online slot, 20p | £0.20 | 500 spins | 4% | £4.00 |
| Live roulette | £5 | 40 spins | 2.7% | £5.40 |
| Auto roulette | £5 | 100 spins | 2.7% | £13.50 |
| Blackjack, basic strategy | £10 | 70 hands | 0.5% | £3.50 |
Look at the two roulette rows. Same game, same bet. The faster wheel costs two and a half times as much, purely because it spins more often.
What the result does not tell you
It’s an average. In a single hour you could win £200 or lose £100 on a slot, and both are normal. The expected loss is where your results drift as the hours pile up. Over a month of regular play the swings start to cancel and the average shows through. Over a year it’s very hard to beat.
It also ignores bonuses, which is deliberate. A bonus can change the maths for a while. The wagering requirement calculator works out whether one actually does.
Finding the numbers
RTP is in the game’s info or help screen, usually as “return to player” or “theoretical RTP”. Some slots come in several RTP versions, so check the one you’re actually playing. For table games the RTP and house edge calculator and the blackjack house edge calculator give exact figures by rules.
Spins per hour is the one people underestimate. Time yourself for five minutes and multiply by twelve. On autoplay with quick spin turned on, 600 or more an hour is common.
Using it to plan, not just to wince
Once you know your hourly cost you can choose it. Halve the bet and you halve the loss. Turn off autoplay and you’ll probably play 30% fewer spins. Switch from a 94% slot to a 97% one and the expected loss drops by half. None of that stops you playing. It just means you decide the price.
To turn an hourly cost into a session plan, try the session budget planner.
Down on the night and tempted to win it back? Run the numbers first with the chasing losses calculator.
Not sure which game costs least? Compare two games’ house edge and hourly loss at best odds in casino.