Wagering Requirement Calculator
This wagering requirement calculator turns a bonus offer into three numbers: the stakes you must place, the number of spins that takes, and the average cost of clearing it. Enter the bonus, the multiple, the game contribution, the RTP and your usual bet, and read the result before you opt in.
This article is part of our slot guides, written to explain the maths and mechanics behind every spin.
What does the wagering requirement calculator tell you?
It answers one question: is this bonus worth taking at these terms? The tool shows the stakes you must place to release the bonus, the spins that represents at your average bet, the expected loss while you clear it, and the expected bonus value left once that loss is deducted.
A positive value left means the bonus is worth something on average. A negative one means that, in the long run, clearing it would cost you more than the bonus is worth. The default entry, a £100 bonus at 35x on a 96% slot at £1 a spin, shows exactly that: £3,500 of stakes, £140 of expected loss and −£40 left.
The tool only does arithmetic on the numbers you enter. It does not read any casino’s terms, so the inputs have to come from the offer you are looking at. It belongs to our slot guides, and the explainer on wagering requirements covers what each term means in the offer itself.
What is the wagering requirement formula?
The calculator uses three steps:
- Stakes required = bonus × wagering multiple ÷ contribution
- Expected loss = stakes required × (1 − RTP)
- Expected bonus value left = bonus − expected loss
The number of spins is the stakes required divided by your average bet. Contribution and RTP are entered as percentages and converted to decimals, so 100% is 1.00 and 96% is 0.96.
The break-even multiple follows from the formula. With a 100% contribution the expected loss equals the bonus when the multiple times (1 − RTP) equals 1. At 96% RTP that is 25x, and at 97% it is about 33x. Reduce the contribution and the break-even falls quickly: at 10% it is 2.5x on a 96% game.
What does each input mean?
| Input | What to enter | Where to find it |
|---|---|---|
| Bonus amount | The bonus value the requirement applies to | The offer page and the full bonus terms |
| Wagering requirement (×) | The multiple, as a plain number such as 10 | The terms, next to the expiry |
| Slot contribution (%) | The share of each bet that counts, such as 100 | The game contribution list |
| Slot RTP (%) | The published RTP of the game you will play | The game’s info screen |
| Average bet | Your usual stake per spin | Your own plan, kept under any max bet |
The bonus amount is the figure the multiple is applied to. If the terms apply it to the bonus plus the deposit, enter that combined sum in the bonus field and read the stakes and the loss. The "value left" line then deducts the loss from the combined sum, so work that one out yourself as the bonus alone minus the expected loss.
The average bet sets the spin count and nothing else: the stakes, the loss and the value left do not change with it. Use it to judge the effort. £1,000 of required stakes is 1,000 spins at £1 but 5,000 spins at 20p, and the time limit in the terms has to cover whichever number you choose. Keep the bet under any max stake the bonus sets.
Contribution is the most often forgotten input. A game that counts 10% multiplies the stakes by ten, and our guide to bonus game weighting shows where the figure sits in the terms.
RTP is the long-run return of the slot. Use the figure for the version you are given, because one game can be published at several settings. Our RTP guide explains how to find it.
Scenario one: £100 at 10x on a slot
Enter 100, 10, 100, 96 and 1. The calculator returns £1,000 of required stakes, 1,000 spins, an expected loss of £40 and £60 of expected bonus value left. This is the shape of an offer at the 10x cap the Gambling Commission applies to bonus funds at UK-licensed casinos from 19 January 2026 (announcement).
On average the offer is worth £60 of the £100. That is a positive result, and it is what you should expect from a requirement set below the break-even.
Scenario two: £100 at 35x on a slot
Change the multiple to 35. The stakes jump to £3,500, the expected loss to £140 and the value left to −£40. The same bonus is now worth less than nothing on average.
The only change was the multiple. That is why the multiple is the first number to look at, and why a bonus with a large headline can be worse than a small one at a low multiple.
Scenario three: £50 at 10x on a game that counts 10%
Enter 50, 10, 10, 99 and 2 for a table-style game with a 99% RTP and £2 bets. Required stakes are 50 × 10 ÷ 0.10 = £5,000, which is 2,500 bets. The expected loss is £50, so the value left is £0.
The high RTP kept the loss low, but the 10% contribution multiplied the stakes by ten. The offer breaks even and gives you nothing on average. If the same game counted 100%, the stakes would be £500, the loss £5 and the value left £45.
How do you use the result to decide?
Check the multiple, the contribution and the expected value left. If the value left is above zero, work out whether the stakes are realistic: divide the stakes by the days you have. £1,000 over 7 days is about £143 a day, and £3,500 over 7 days is £500 a day.
Then compare with the alternative of not taking the bonus. Declining costs nothing and leaves your deposit free to withdraw. At UK-licensed casinos, the Commission’s guidance says players must be able to withdraw their deposit balance at any time, including while a bonus is active (restrictions on withdrawing deposit and deposit winnings).
For current offers to test in the calculator, see our UK slot bonuses compared page and take the figures from each operator’s own terms.
More slot guides
- how online slots work
- RTP explained
- slot volatility explained
- max cashout limits
- live dealer vs RNG
- wagering requirements explained
- bonus game weighting
- sticky vs non-sticky bonuses
- the max bet rule on bonuses
- how to value free spins
- how crash games work
- Plinko odds explained
- the maths behind Mines
- slots maths course
Frequently asked questions
How do I calculate a wagering requirement?
Multiply the bonus by the multiple. A £50 bonus at 20x needs £1,000 of stakes. If the games you play count less than 100%, divide by the contribution.
What does expected loss mean in the calculator?
It is the stakes you must place times the house edge. At 96% RTP the house edge is 4%, so £1,000 of stakes costs £40 on average.
Why is the value left negative?
The expected loss from clearing the requirement is larger than the bonus. At 96% RTP and 100% contribution, that happens above 25x.
What contribution should I enter?
The percentage the bonus terms give for the game you will play. Slots often count 100%, but check the list, because table and live games can count 10% or less.
Does the calculator include max bet and max cashout?
No. It models stakes and average loss only. Read those terms separately and treat the result as an upper bound on what the offer is worth.
What RTP should I use?
The published RTP of the game you will play. If you do not know it, 96% is a common figure, but check the game’s info screen.
Responsible gambling. You must be 18 or over to gamble. A calculator tells you what a bonus is worth on average, and it cannot tell you what you can afford to lose. Set deposit and time limits first. GamCare offers free, confidential support on 0808 8020 133, and BeGambleAware provides further guidance. Our responsible gambling page lists the tools available.