What is EV (Expected Value) for a casino bonus?

EV stands for expected value. It tells you how much a bonus earns or costs you on average in the long run, expressed in euros. A positive EV means the bonus offers a mathematical advantage. A negative EV means the bonus costs you money over time. Most Dutch welcome bonuses fall into the second category.

The formula

EV is the difference between what you actually receive as a bonus and what you lose on average while meeting the wagering.

Example: how a number appears

Say you deposit €100 at a casino with a 100% match up to €250, 30× wagering on the bonus, and slots at 96% RTP. Compare that to a casino offering 50 free spins of €1 without wagering. Same deposit, very different story.

The match bonus looks bigger, but the wagering eats it. The spins are small, but you never have to roll them over. Same starting capital, €68 difference in expected outcome.

What EV is and is not

EV is a long-run average. In a single session, variance, meaning luck, swings your result much more than EV does. A bonus with +€5 EV can land at −€200 or +€300 on any given evening. Only across many bonuses does the average outcome drift toward the EV.

Why EV is the only honest comparator

Casinos advertise with match percentages and round numbers. “100% up to €500!” reads better than “EV −€12 per €100 deposited.” Only the second number tells you what the bonus actually costs or earns. On BonusWijs we compute EV for every Dutch welcome bonus on a standard deposit. You see the number, you see the assumptions, and you decide whether the deal fits your budget and your schedule.

Two things drive EV the hardest: the wagering requirement (how often the bonus must be rolled over) and the RTP of the game used to clear it. One percent RTP less, or 5× higher wagering, can flip EV from positive to negative.