Calculating Bonus Wagering Requirements — Step by Step with Real Numbers

'100% bonus up to €500 + 200 free spins' — the typical welcome banner. What it doesn't show: whether you can clear that bonus with positive or negative expected value. This article works through a complete bonus and gives you a formula to evaluate any offer in 60 seconds.

The four dials of every bonus: (1) **Wagering multiplier** — how often you must turn over bonus (or bonus + deposit). (2) **Game contribution** — what percentage of your stake counts toward wagering. (3) **Max cashout cap** — maximum withdrawal from the bonus. (4) **Max bet per spin/hand** during wagering. Each of these can turn a seemingly generous bonus into a mathematical trap.

The core formula: **Expected loss while wagering = wagering requirement × house edge**. Expected bonus value = bonus amount − expected wagering loss − cashout cap loss. If the result is positive: +EV bonus. If negative: −EV — a bet you lose on average.

**Sample bonus:** 100% up to €200, 35× wagering on bonus, min deposit €20, max cashout 4× bonus, slots 100% contribution, blackjack 10%, max bet €5/spin, valid 30 days. You deposit €200, get €200 bonus, hold €400 playable.

**Step 1 — Wagering requirement:** €200 bonus × 35 = €7,000 wagering. (Watch out: some operators apply 35× (bonus + deposit) = €14,000. Read the fine print — that doubles your expected loss.)

**Step 2 — Expected loss while wagering:** On slots with RTP 96% (house edge 4%): €7,000 × 0.04 = €280 expected loss. RTP 97%: 7,000 × 0.03 = €210. On basic-strategy blackjack (0.5% edge), the 10% contribution means 10× more turnover required = €70,000. Expected loss: 70,000 × 0.005 = €350. Despite the lower house edge, blackjack wagering is more expensive here.

**Step 3 — Cashout cap:** Max cashout = 4 × €200 = €800. If your balance at the end of wagering is above €800, you can only withdraw €800 (rest forfeits). For most players the result sits around the mean (€400 − €280 = €120) — the cap is irrelevant. On high-variance slots (e.g. bonus-buy slots) the cap can eat 30–50% of expected value.

**Step 4 — Expected bonus value:** You get €200 free, expect to lose €280 wagering. Expected value = 200 − 280 = **−€80** (before cap loss). This bonus is on average a losing bet. You lose €80 in EV AND you have to deposit €200, of which only an expected €120 remains — less with the cap.

**When IS a bonus +EV?** Rule of thumb: when **wagering × house edge < bonus amount**. At 35× wagering and 4% house edge, you'd need less than 1.43% house edge to make the bonus positive. That requires either (a) basic-strategy blackjack at 100% contribution (very rare), or (b) slots with RTP > 98.57% (also rare). Reality: most bonuses are mathematically −EV. They can still make sense for entertainment value — just not for your bankroll growth rate.

**Step 5 — Check max bet:** €5 max bet and €7,000 wagering means at least 1,400 spins. At 5 seconds per spin that's about 2 hours non-stop. Realistically: 8–12 hours spread over 30 days. Exceeding max bet (even once) often forfeits the entire bonus + winnings — a hidden but common trap.

**Quick-rating table:** At 4% slot edge with 'wagering on bonus only': 20× = 0.80×bonus expected loss → borderline. 30× = 1.20×bonus → mildly −EV. 40× = 1.60×bonus → clearly −EV. 50× = 2.00×bonus → strongly −EV. 60×+ = effectively unclearable with positive EV. With 'bonus + deposit' wagering you double every value.

**Bonus-type check:** No-deposit: always +EV cash-flow wise, often −EV after wagering. Welcome-match (100%): mostly −EV, but psychologically valuable for new players. Reload bonus (50%): usually strongly −EV, almost always skip. Cashback (10–20%): one of the few mostly +EV bonus types because no wagering applies. Free spins: calculate as no-deposit with EV = spin value × count × RTP − wagering × house edge.

Tools on Casinokeller: The house edge calculator gives the edge for any game + RTP. The Kelly calculator shows whether a +edge bonus suits your bankroll size. For full bonus rating: copy terms, multiply wagering × house edge, compare with bonus.

Related articles: 'Why bonus terms are usually a trap' (psychological angle), 'No-deposit bonus 2026' (no-deposit special case), 'Kelly criterion with casino examples' (stake sizing). Glossary: 'Wagering', 'RTP', 'House edge'.

Bottom line: A bonus isn't a gift question, it's a math question. Wagering × house edge vs. bonus amount — knowing those three numbers tells you in 60 seconds whether to take it. The honest reality: 90% of advertised bonuses are mathematically −EV. The few +EV bonuses (cashback, low wagering, high contribution) rarely get the loudest banners — they live in the fine print or VIP sections. Those who can do the math find them. Those who only click finance the marketing budgets.