About BonusMath
Methodology: how we value and rank casino bonuses
BonusMath exists because bonus banners compare the wrong number. A 400% package and a 100% match tell you nothing until you know the wagering, the base and the games. We publish one formula, apply it the same way to every offer and show the working.
The formula
Every offer is reduced to an expected value on a 100 deposit (dollars, or euros where the casino's terms are in euros), with slots at 96% RTP and 100% contribution, and a $1 stake. The steps are: bonus = min(deposit × match, cap); turnover = wagering base × multiplier ÷ contribution; expected loss = turnover × house edge; expected value = bonus − expected loss + net free-spin value + rakeback. Free-spin value is expected winnings minus the expected cost of wagering them, never below zero. Rakeback offers are valued on $4,000 of turnover — what a 40x bonus requires on $100 — so they sit on the same scale. The result is floored at minus the deposit, since that is the most a player can lose.
The Bonus Value Score maps that expected value to 0–100: 50 + 50 × EV ÷ deposit. You can reproduce every number in the calculator; the site build uses the very same code.
How the rank is set
True value is the largest factor, but not the only one. A bonus is only as good as the casino that pays it. Our rank weights:
| Factor | Weight | What we look at |
|---|---|---|
| True value of the welcome offer | 40% | Expected value and Bonus Value Score on standard inputs |
| Rule friendliness | 20% | Sticky vs non-sticky, max bet, time limit, excluded games, caps |
| Payout speed | 20% | How quickly approved crypto withdrawals arrive |
| Casino quality | 10% | Game library, support, usability |
| Reputation | 10% | Track record and public player feedback |
That is why the order in our rankings is not a sort by true value. Rollbit and Duelbits score well on value with rakeback, but a rakeback offer gives no upfront balance and rewards volume, so they sit lower overall. BitGuruz is the clearest case the other way: on our assumed wagering (30x the bonus — check the current terms) its welcome bonus has one of the lowest true values in our table, but it leads on payout speed — it is the only casino we list with instant crypto cashouts — and on casino quality, match size and reputation. We rank it #1 overall and say plainly in its review that the bonus is expensive to clear and optional. If bonus value is your only criterion, use the true-value column instead of the rank.
Terms snapshots
Casinos change offers often. Every term on this site is labelled "terms checked october 2026, may change". We re-check the ranked offers monthly and whenever a reader tells us something has changed. Where a casino describes its offer in a way that does not fit the calculator — for example a gradual-unlock bonus — we model the closest equivalent and say so in the review. Multi-deposit packages are modelled on the first deposit.
What we do not do
- We do not promise wins. Expected value is an average; individual results vary widely.
- We do not adjust numbers for commercial reasons. Commissions may affect which casinos we cover; they never change a calculated value.
- We do not publish licence numbers or legal claims we cannot verify. Check licensing details on each casino's own site.
- We do not recommend gambling to anyone under 18, or to anyone who is struggling to control their play — see responsible gambling.
The team
BonusMath is written by a small editorial team. We use pen names to keep our personal accounts separate from our work at casinos.
Lead analyst
Mara Quill
Builds and maintains the bonus formula, and re-runs every ranked offer when terms change. Spent years modelling sports-betting margins before moving to casino promotions.
Terms auditor
Theo Rask
Reads the full bonus terms, the general terms and the cashier rules for each casino, and logs every clause that changes the math: max bet, game weighting, time limits and withdrawal caps.
Responsible gambling editor
June Okafor
Reviews every page for tone and safer-gambling information, and keeps the helpline list current.
Contact and corrections
Spotted an out-of-date term or an error in the math? We correct mistakes quickly and note material changes in the affected review. Every guide shows the formula it relies on, so you can check our work: start with wagering requirements explained.