How casino bonuses actually work
Updated 2026-08-08 · about 4 minutes to read
If you have ever looked at "100% up to $1,000" and wondered what the catch is, this page explains it in plain English. No maths background needed. Every example uses a real casino's published terms, and we link to those terms so you can check us.
1. The house takes a cut of every bet, not of your deposit
This is the bit that surprises people, and everything else follows from it.
Casino games are built so the house keeps a small slice of everything that is bet. A slot advertised at "96% RTP" pays back 96% of everything wagered through it over time. The remaining 4% is the house edge.
The catch is that this applies to every bet, not to the money you put in. Bet the same $100 twenty times over and you have wagered $2,000 — so you should expect to be down about $80, not $4. Your money goes round and round, and the house takes a slice on each lap.
2. A bonus is not cash — it is cash with a lap count attached
Bonus money cannot be withdrawn straight away. First you have to place a certain amount of bets. That is the wagering requirement, written as something like "35×".
35 times what, though? There are two possibilities, and they are not close:
- 35 × the bonus, or
- 35 × your deposit plus the bonus
The second means roughly twice as much betting for the same offer. Adverts almost never say which one applies — it is in the terms, and it is the single most important sentence in them.
A real example — Shuffle.com, from their own published terms
You deposit $1,000. They add $1,000 of bonus. Their terms say the wagering is 35× the deposit and the bonus together:
bets you must place = ($1,000 + $1,000) × 35 = $70,000
what that costs you = $70,000 × 4% = $2,800
the bonus is worth = $1,000 − $2,800 = −$1,800
To collect a $1,000 bonus you have to put $70,000 through the games. That is the part the advert never mentions.
3. What "real value" means
Real value is what a bonus is worth on average, after subtracting what the required betting costs you. It is not a prediction of your night. You might win; someone will. It is what the offer is worth if a great many people claimed it.
Most match bonuses come out negative, and that is normal rather than sinister. It is simply what a wagering requirement does. It does not mean the casino is cheating you — it means the bonus is worth less than the number on the banner, and usually by a lot.
The deadline matters as much as the maths
Most bonuses have a time limit, and most also cap how much you can bet while clearing one. Put those two together and you can work out whether finishing is even physically possible. Assuming roughly five seconds per spin and betting the maximum allowed the whole time:
| Casino | Must bet | Max bet | Time allowed | Non-stop play needed |
|---|---|---|---|---|
| Crashino | $35,000 | $5 | 7 days | 1.4 hours a day |
| 21.com | €20,000 | €5 | 30 days | 0.2 hours a day |
| Fairspin | $112,500 | $10 | 3 days | 5.2 hours a day |
If a bonus needs five hours of continuous spinning every day for three days, most people will simply not finish it — and an unfinished bonus is forfeited along with anything won from it. In that case the real value is worse than the figure above, not better.
4. The other kinds of offer — and why they are often better
"Bonus" covers several quite different things. The ones with no wagering requirement are usually worth far more than the ones with a big headline percentage, because nothing forces you to keep betting.
| Type | What it is | What to check |
|---|---|---|
| Welcome / deposit match | They match your deposit with bonus money | The wagering, and whether it applies to the bonus or to deposit + bonus |
| Cashback | A share of what you lost comes back. Lose $1,000 at 20% and $200 returns | Whether the returned money has wagering of its own |
| Rakeback | A share of the house's cut comes back — whether you win or lose | The rate, and whether it is fixed or only "up to" |
| Lossback | Losses inside a short window are refunded, usually as credit | How much you would need to lose to reach the advertised cap |
| Free spins | Spins at a fixed stake on chosen games | Winnings usually become bonus money with wagering attached |
Cashback and rakeback are easy to confuse. Cashback is a share of your losses, so it only pays when you lose. Rakeback is a share of the house's edge, so it pays on every bet either way. Rakeback amounts are small — 5% of the edge on a $1,000 bet at a 2% edge returns about $1 — but it is normally real money with no strings.
5. What to look for before claiming anything
- Does the wagering apply to the bonus, or to deposit + bonus? Roughly doubles the betting.
- Is there a maximum you can withdraw? Some cap winnings at the bonus amount, so a big win pays nothing extra.
- How long do you have, and what is the maximum bet? Together these decide whether finishing is realistic at all.
- Which games count? Slots usually count fully; table games and live dealer often count 10% or less, which multiplies the betting needed.
- Does anything come back with no wagering? That part is worth exactly what it says.
Where to go next
We work this out for every casino we list, using their own published terms. See every offer ranked within its own type, or the arithmetic behind our numbers with a link to each casino's terms page.
Gambling can be addictive, and no bonus changes the fact that these games are built to make money. Never deposit money you cannot afford to lose. Play responsibly. 18+.