Slot Bonus Expected Value — How to Calculate It

Expected Value (EV) is the most useful metric for comparing slot bonuses. It tells you, on average, whether a bonus is mathematically worth claiming and how much it is genuinely worth.

The Formula

Worked Examples

10Bet: £50 at 8× → EV = £50 − (8 × £50 × 0.04) = £50 − £16 = +£34

Casumo: £25 at 10× → EV = £25 − (10 × £25 × 0.04) = £25 − £10 = +£15

Playzee: £150 at 10× → EV = £150 − (10 × £150 × 0.04) = £150 − £60 = +£90

Use the calculator in the sidebar to calculate EV for any bonus instantly. Post-January 2026 UKGC cap, every qualifying UK operator bonus has positive expected value — claiming is always better than not claiming, assuming you intended to play anyway.

→ Best Slot Welcome Bonuses · Wagering Requirements Guide