A 100% deposit bonus sounds like free money. It isn't. Once wagering requirements meet a low-RTP slot, the expected cost of clearing a bonus can exceed the bonus value itself. This guide shows you the maths - and a calculator to run your own numbers.
By Marcus Reid·Published May 27, 2026·10 min read·Intermediate guide
Expected loss clearing $100 bonus at 30x on a 6% edge slot
30-50x
Typical wagering requirement range
$60
Same bonus at 30x on a 2% edge slot
10-20%
Typical slot contribution to wagering
How Wagering Requirements and RTP Interact
Here's how it works. You deposit $100, get a $100 bonus, and face a 30x wagering requirement. That means you must spin through $3,000 of total bets before the bonus converts to withdrawable cash. The casino's cut comes from the house edge on every one of those $3,000 in bets.
At a 4% house edge (96% RTP slot), that's an expected cost of $120. Your bonus was $100. You're already expected to lose $20 more than the bonus gave you - before you even think about your deposit money.
At a 6% house edge (94% RTP), the same bonus costs $180 to clear. At 8% (92% RTP), it's $240. Same wagering requirement. Same bonus. Very different cost - and RTP is the only variable that changes it.
Example: $100 bonus × 30x wagering × 6% house edge = $180 expected cost to clear
Worth noting: Wagering requirements are sometimes quoted as "deposit + bonus" rather than just the bonus amount. A 30x requirement on a $100 deposit + $100 bonus means $6,000 in required bets - not $3,000. Always check the T&Cs for exactly what the multiplier applies to.
The Wager Path - Where Your Money Goes
The bars below show exactly what happens to $3,000 in wagering at different RTP levels. All based on long-run expected values - your actual session will vary, but over thousands of spins this is where the money flows.
97% RTP (3% edge)
$2,910
-$90 cost
96% RTP (4% edge)
$2,880
-$120 cost
95% RTP (5% edge)
$2,850
-$150 cost
94% RTP (6% edge)
$2,820
-$180 cost
92% RTP (8% edge)
$2,760
-$240 cost
92.37% (Le Zeus, Pistolo)
$2,771
-$229 cost
The Le Zeus row is a real figure from our Pistolo test. If you were clearing a $100 bonus with 30x wagering on that slot, the expected clearing cost is $229 - more than double what the same bonus costs on a well-configured 96% slot.
The compounding problem: Most bonus terms restrict which games count toward wagering - and slots typically count at 10-20%, not 100%. That means to clear a nominal $3,000 wagering requirement on slots, you may need to spin through $15,000-$30,000 in actual bets. At 6% house edge, the cost multiplies accordingly.
4 Hidden Costs That Make Bonuses More Expensive Than They Look
Hidden Cost 01
Game contribution rates
Most bonus terms list a contribution percentage per game type. Slots often contribute 10-20% toward wagering - meaning $1 wagered on a slot clears only $0.10-$0.20. To clear a $3,000 requirement on 10% contribution slots, you need $30,000 in actual bets. At any house edge, that's a large expected loss.
Hidden Cost 02
Restricted high-RTP games
Casinos frequently exclude the highest-RTP slots from bonus play entirely - or cap their contribution at 0%. The games left eligible are often lower-configured variants. So the slots available for clearing your bonus tend to be the ones with the worst house edge.
Hidden Cost 03
Max bet restrictions
Bonus terms typically cap the maximum stake per spin while a bonus is active - often $2-$5 regardless of your deposit size. This controls how quickly you can clear the requirement, but it also means you can't use your normal stake to manage session variance.
Hidden Cost 04
Time limits and forfeiture
Most bonuses expire in 7-30 days. If you don't clear the wagering in time, both the bonus and any winnings from it are forfeited. Time pressure pushes you to play faster and at higher stakes - which tends to increase variance and expected cost simultaneously.
Bonus Value Calculator - Is the Offer Worth Taking?
Enter the bonus details and the RTP of the slot you'd use to clear it. The calculator shows the expected clearing cost and whether the bonus has positive or negative expected value.
Bonus Expected Value Calculator
$3,000
Total bets required at this contribution rate
$120
Expected clearing cost (house edge × total bets)
-$20
Net expected value (bonus minus clearing cost)
How to use this: Start with contribution at 100% to see the baseline. Then lower it to the actual slot contribution in the T&Cs (often 10-20%) to see the real cost. The jump is usually striking.
Good Bonus vs Bad Bonus - What to Look For
Frankly, most bonuses are negative expected value at standard casino slot configurations. That's not a bug - it's the point. But some bonuses are significantly better than others. Here's what separates them.
Factor
Good sign
Red flag
Wagering requirement
10-20x or lower
40x+ - very hard to clear profitably
What it applies to
Bonus only - not deposit + bonus
Deposit + bonus - doubles the required bets
Slot contribution
100% or close to it
10-20% means 5-10x more actual bets needed
Game restrictions
All slots eligible including high-RTP variants
High-RTP slots excluded or capped at 0%
Max bet cap
$5+ per spin while bonus is active
$1-2 - forces very long session to clear
Time limit
30 days+ to clear
7 days or less - pressure to rush and lose more
No deposit bonus
Small amount, reasonable wagering
Tiny amount, 50x+ wagering - almost impossible to clear
The honest summary: treat a bonus as a way to extend your session - not as extra money. If the wagering is reasonable and slots contribute at 100%, a 20x bonus on a good RTP slot can be close to break-even. Anything with 40x+ wagering on slots at 10% contribution is almost always negative expected value. The maths is that simple.
Bottom line: Before accepting any bonus, run the numbers in the calculator above. Use the actual slot RTP from our database - not the provider's published max. The casino-configured figure is what you'll actually experience during wagering.
Marcus Reid
iGaming Data Analyst
The clearing cost formula in this guide is straightforward maths - but most bonus promotions are designed to obscure it. Contribution rates buried in T&Cs, restricted game lists, and deposit+bonus wagering multipliers all compound the true cost. The calculator here applies the same model we use internally when evaluating whether a casino's bonus offer is worth recommending.
RTP Database
