How this works
This uses the expected value formula that matched bettors use. It shows the statistical average outcome — not a guarantee for your specific session (variance is real).
Example: 30x wagering at 96% RTP on £50 bonus
Playthrough = £50 × 30 = £1,500 in bets required.
Expected loss = £1,500 × 4% = £60.
Net value = £50 − £60 = −£10. Skip it.
Example: 10x wagering at 96% RTP on £50 bonus
Playthrough = £50 × 10 = £500 in bets required.
Expected loss = £500 × 4% = £20.
Net value = £50 − £20 = +£30. Worth claiming.
Break-even points by RTP
| Slot RTP | Break-even wagering | What it means |
|---|---|---|
| 97% | 33x | Under 33x = positive value |
| 96% | 25x | Under 25x = positive value |
| 95% | 20x | Under 20x = positive value |
| 94% | 16x | Most 35x+ offers = negative value |
Things to keep in mind
- Variance: Slots are high variance. Your actual session can differ a lot from the EV figure — this is the long-run average, not what happens every time.
- Game weighting: Blackjack and roulette usually count at 10-20% toward wagering. Playing table games effectively multiplies your required playthrough by 5-10x. See my game weighting guide.
- Max bet rule: Exceeding the per-spin limit (usually £5) during wagering can void your bonus. The calculator can't account for accidental violations.
Why most casino bonuses are negative value
The UK casino industry averages 35x-40x wagering requirements. At 96% RTP, the break-even point is 25x. This means the majority of welcome bonuses offered in the UK market are mathematically designed to cost you more than they give you.
This isn't hidden — it's just that most players don't run the numbers. A £200 bonus sounds generous until you realise the £8,000 playthrough requirement will cost you £320 in expected losses. That's why I built this calculator: to make the maths obvious in 10 seconds.
How casinos set wagering requirements
Casinos use wagering requirements to balance two things:
- Attracting players: Big bonus numbers get clicks. "£500 free" sounds better than "£20 free".
- Protecting margins: High wagering ensures most players lose more than the bonus value before withdrawing.
The sweet spot for casinos is a wagering level high enough to be profitable, but not so high that informed players avoid them entirely. 35x-40x is that sweet spot for the industry. Under 20x is where casinos start giving up real value to attract players.
When to ignore the calculator
Expected value isn't everything. There are legitimate reasons to take a negative-EV bonus:
- Entertainment value: If you're playing for fun anyway, the bonus extends your playtime
- Testing a casino: A small negative-EV bonus lets you test withdrawal speed and support quality cheaply
- Variance hunting: High volatility slots can hit big wins regardless of EV — you might not care about long-run averages
The calculator tells you the mathematical reality. What you do with that information is your call.
Frequently asked questions
Is this calculator accurate?
It's mathematically accurate for the inputs you provide. The formula is standard expected value calculation used by matched bettors and advantage players. Real-world results will vary due to variance, but over thousands of bonuses, the averages converge to these figures.
What RTP should I use?
Use the RTP of the slot you'll actually play. If you don't know, 96% is a reasonable estimate for popular UK slots. Higher-RTP slots (97-98%) shift the break-even point in your favour. Lower-RTP slots (94-95%) make wagering more costly.
Does this account for game weighting?
No — the calculator assumes 100% contribution (slots). If you're playing games with reduced weighting, your effective wagering is higher. For example, 10% weighting on a 30x bonus = 300x effective wagering. Stick to slots during wagering.
Why does "deposit + bonus" matter so much?
If wagering applies to deposit + bonus combined, you're betting twice as much for the same bonus. A 30x bonus-only requirement is £1,500 playthrough on a £50 bonus. A 30x deposit+bonus requirement is £3,000 playthrough. Always check which structure the casino uses.