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Casino bonus EV explained

By Dana Reeves, Lead Bonus Analyst · Updated 2026-06-23

How Bonus EV Is Calculated

'Expected value' (EV) is the one number that tells you whether a casino bonus is actually worth claiming. It is the average amount you would keep (or lose) if you cleared the same offer many times. This guide shows the formula, why the headline percentage is misleading, the factors that move EV, a full worked example, and how to read any offer in under a minute.

The formula

EV = Bonus − (Bonus × Wagering × (1 − RTP)). With RTP assumed at 0.96, a $200 bonus at 35x = $200 − ($200 × 35 × 0.04) = $200 − $280 = −$80. Negative EV means that, on average, you expect to lose money clearing the bonus — the wagering costs more than the bonus is worth.

Why the headline percentage is misleading

A '300% up to $600' bonus sounds far better than '100% up to $200', but the match size barely matters once wagering is applied. What decides EV is the combination of bonus size, wagering multiplier, game RTP and max cashout. A smaller bonus at 10x routinely beats a huge one at 45x. Operators lead with the percentage precisely because it is the least informative number.

40x

Typical wagering requirement

96%

Average slot RTP

House edge on that RTP

$100

Example bonus size

RTP and variance

RTP is the long-run return of a game; 96% is a common slot baseline. Higher-RTP games clear wagering more cheaply. Variance is separate — it's the swing around that average. Low EV with high variance means you'll occasionally win big but usually lose; positive EV is what makes the bet worth taking at all. EV tells you whether to play; variance tells you how bumpy the ride is.

✓ RTP sets the average, variance sets the spread

Two games with identical 96% RTP can produce very different real-world outcomes — high-variance slots swing further from the average, so your actual result on any single session can look nothing like the EV math.

Game contribution changes the real EV

If table games contribute only 10% to wagering, clearing the bonus through them multiplies your turnover — and therefore your expected loss — roughly tenfold. Always compute EV using the games you'll actually play at their real contribution rate, not the slot assumption.

Typical wagering contribution by game

Game type	Contribution to wagering
Slots	100%
Roulette	10–20%
Blackjack	5–20%
Live dealer tables	10%
Video poker	0–10%

Max cashout caps your upside

Many bonuses cap how much you can withdraw from bonus winnings (e.g. 5× the bonus). That cap truncates the good outcomes while you still bear all the downside, which lowers true EV below the simple formula. If a bonus has a tight max cashout, treat the headline EV as optimistic.

⚠ A cap turns a bonus into a lottery ticket

If max cashout is set at $200 on a $100 bonus, any big win beyond that is void — this caps your upside while the wagering-driven expected loss stays uncapped, dragging real EV further negative.

Read any bonus in a minute

1) Find the bonus amount and wagering multiplier. 2) Multiply them to get required turnover. 3) Take ~4% of that turnover as expected loss (at 96% RTP). 4) Compare it to the bonus: if the loss exceeds the bonus, skip it. For an exact figure that accounts for your numbers, use the free EV calculator.

When a bonus IS worth it

Positive-EV offers do exist: low or zero wagering, cashback/rakeback paid as real cash, no-deposit bonuses, and high-RTP-eligible promotions. These are worth claiming. The point of EV is not to avoid all bonuses — it's to claim the good ones and skip the traps.

★ Low wagering beats a big headline number

A 5x-wagering 50% bonus almost always beats a 40x-wagering 200% bonus in real EV — smaller multipliers reduce the expected loss far more than a bigger match percentage adds value.

See it applied

Every BonusOz review shows this calculation for that casino's specific offer, plus a clear claim-or-skip verdict. Start with the lowest-wagering options in our wagering guide.