Bonus Wagering Calculator Work Out What a "Free" Bonus Actually Costs You

A worked example

Take the offer the calculator loads with: a £50 bonus at 35x wagering, cleared on a slot running 96% RTP, with the requirement applying to the bonus only.

The wagering requirement is 35 × £50, so you must stake £1,750 before any withdrawal. At 96% RTP the house keeps 4% of everything staked, so the expected cost of putting £1,750 through the game is 4% of £1,750 — £70. You were given £50 and it costs an average of £70 to unlock it, so the net expected value is −£20. The offer is worth less than nothing.

Now change one thing. If the same casino applied the wagering to deposit plus bonus and you deposited £50, the requirement becomes 35 × £100 = £3,500, the expected cost doubles to £140, and the net value falls to −£90. Identical headline bonus, nearly five times worse.

Two levers move the answer, and neither is the size of the bonus: the multiplier and the RTP of the game you clear it on. A £50 bonus at 20x is worth taking on a 96% slot; the same bonus at 35x is not, unless you can find a game above roughly 97.14% RTP.

What this calculator doesn't include

Two terms in the small print can change the real cost significantly, and neither is modelled above.

Game weighting. Not every game contributes equally to the requirement. Slots usually count at 100%, but table games are often weighted at 10% or less — meaning £1 staked on roulette might only reduce the requirement by 10p, so you'd need ten times the turnover to clear it. Some games are excluded entirely. Always clear wagering on a game that counts at 100%, and check the excluded list before you start.

Max bet limits. Most bonus terms cap the stake per spin while wagering is active, typically around £5. Breaching it even once can void the bonus and any winnings from it, regardless of how much of the requirement you'd already cleared. There is often a time limit too — commonly 7 to 30 days — and an unmet requirement at expiry usually forfeits the balance.

Why a higher-RTP slot clears wagering more cheaply

The wagering requirement is a fixed amount of turnover. What varies is how much that turnover costs you, and that is decided entirely by the RTP of the game you clear it on. The requirement doesn't change — the expected loss on the way through it does.

Clear £1,750 on a 94% slot and the expected cost is 6% of it: £105. Clear the same £1,750 on a 96.71% slot and it's 3.29%: £57.58. Same bonus, same requirement, same casino — a difference of nearly £50 decided by nothing more than which game you opened. On a £50 bonus, that gap is the whole offer.

This is why the RTP of the game you pick to clear a bonus matters more than the headline size of the bonus itself. Use the slot database to find a high-RTP game that counts at 100% toward wagering, and check that the specific casino runs the higher build — the same title is frequently offered at several different RTPs, and the version you get is the operator's choice, not the provider's.

To see what a given RTP costs in isolation over your own stake and spin count, use the RTP Calculator. To compare candidate games side by side before you commit, use the RTP Comparison Tool.

The honest summary

Most bonuses with a standard 35x requirement have a negative expected value on a typical 96% slot. That doesn't make them a scam — it makes them what they are: a marketing cost the operator has priced to come out ahead. A bonus is worth taking when the multiplier is low, the RTP of your chosen game is high, and the wagering applies to the bonus alone. When all three go the other way, the correct move is to decline the offer and deposit without it.