Slot RTP Calculator See What a Percentage Actually Costs You

Enter a slot's RTP, your stake per spin and how many spins you plan to play. We'll show what that works out to over the long run — and how much a small RTP difference really adds up to.

RTP %

%

Stake per spin

£

Number of spins

Results update automatically as you type.

Your expected results

Total wagered£500.00Stake × spins

Expected return£480.00Wagered × RTP

Expected loss£20.00The house edge cost

House edge4.00%100% − RTP

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This is a long-term statistical average — not a session prediction

These figures show what happens on average across millions of spins. Any real session can win or lose far more than the "expected" numbers above. RTP describes the maths of the game over the long run; it does not tell you what will happen to your money tonight.

A worked example

Say you play a 96% RTP slot at £1 per spin for 500 spins. You'll have wagered £1 × 500 = £500 in total. Because the game returns 96% on average, your expected return is £500 × 0.96 = £480 — meaning an expected loss of £20, which is exactly the game's 4% house edge applied to your total stake.

But that £20 is a long-run average, not a forecast for your 500 spins. Real sessions vary wildly because of volatility. On a high-volatility slot you might lose your whole £500 chasing a bonus that never lands — or turn it into thousands on one lucky free-spins round. The RTP maths only reveals itself over an enormous number of spins; any single session is dominated by chance.

Why the version you play matters

Run the calculator twice — once at 96.71% and once at 94.60% — and you'll see the cost of the "version trap" in pounds. Those are the two builds of Big Bass Bonanza, the same game, at different casinos. Over 10,000 spins at £1 that gap is £211, which is why checking the deployed RTP before you play is worth the thirty seconds it takes.

Use the slot RTP database to find which casinos run the top version, or browse the highest RTP slots to start from the best-paying games available.

Frequently asked questions

Does RTP predict what will happen in my session?

No. RTP is a theoretical average measured over millions of spins. In a single session your result is driven by chance and volatility, and can differ dramatically from the "expected" figure — that's why some players hit big wins and others lose their whole balance on the same game.

What counts as a good RTP?

Anything at or above roughly 96% is considered decent for an online slot, and 97%+ is very good. The very highest-RTP slots reach 99%+. Below about 94% is on the stingy side. Remember the same slot can be deployed at different RTPs, so always check the version at your casino.

How is house edge related to RTP?

They're two sides of the same coin: house edge = 100% − RTP. A 96% RTP slot has a 4% house edge, meaning the casino keeps 4% of everything wagered on average over the long run. Lower house edge (higher RTP) means better long-term value for you.

Can I use this to work out a winning strategy?

No — and be wary of anyone who says otherwise. Every result is independent and every game carries a house edge, so no staking pattern changes your expected return. This calculator shows what a game costs on average; it can't turn a negative expectation into a positive one.

Written by Mark Gruetze, RTP & Volatility Analyst · Reviewed by Jon Pill · Last updated Jul 2026