Slot Bonus Expected Value — How to Calculate It

Expected value (EV) tells you, on average, what a bonus is worth after you have met its wagering requirement. It is the single most useful number for comparing offers.

The formula

Worked examples

£50 bonus at 10x: 50 − (10 × 50 × 0.04) = 50 − 20 = +£30.

£100 bonus at 8x: 100 − (8 × 100 × 0.04) = 100 − 32 = +£68.

£25 no-deposit at 10x (capped £50 win): positive EV but limited by the win cap — the cap, not the wagering, defines the real ceiling.

What EV does and does not tell you

EV is a long-run average, not a prediction for a single bonus. Variance means your actual result can be far above or below it — especially on high-volatility slots, where you may never clear the wagering at all. Use EV to compare offers, choose lower wagering and lower-volatility slots to clear bonuses, and always read the maximum-bet and game-contribution terms. See our wagering guide.