A casino bonus is not money you can withdraw. It is money you have to bet a set number of times first. That number is the wagering requirement, and it decides what the bonus is worth.
What the multiplier means
A 35× requirement on a 100 bonus means you must place 3,500 in bets before the bonus and anything won from it can be withdrawn. You are not expected to lose 3,500. You lose the house edge on each bet.
A worked example
Take that 100 bonus at 35× on a game that returns 96% to players. Betting 3,500 costs 4% on average, which is 140. So the 100 bonus costs about 140 to clear and is worth roughly minus 40 on average. At 20× the same bonus costs about 80 to clear and is worth about plus 20.
Bonus only, or bonus plus deposit
Check what the multiplier applies to. If 35× applies to the bonus and your deposit, a 100 deposit with a 100 bonus means 7,000 in bets, not 3,500. That one line doubles the cost.
The rules that catch people out
Maximum bet. Many offers cap each bet while you are wagering. One bet over the cap can void the bonus.
Game weighting. Slots usually count in full. Table games may count a fraction, or not at all.
Expiry. Unfinished wagering is forfeited when the clock runs out.
A quick way to judge an offer
Put the numbers into the bonus calculator. If the average value is negative, the bonus costs more to clear than it gives you. No-wager rewards such as rakeback or cashback are simpler: what you receive is what you keep.
