Book of Luck slot: RTP and max win
Book of Luck is a high-volatility slot by Knockout Labs on Stake Engine, released 2 Aug 2026. Its base game returns 96.70%, above the median Engine slot (96.02%) and higher than 86% of them. The top payout is 20,000× the bet, bigger than 59% of Engine slots; from a base spin it lands about once every 2,857,171 spins. It has 4 bonus buys priced at 100× to 250× the bet; the best returns 96.70%, so each buy costs 3.30× the bet on average over the long run. It is the No. 1869 most played Engine slot over the last 30 days.
Every mode, side by side
Costs are multiples of the base bet. Odds come from the published outcome table for v9. "Returns the cost" counts rounds that pay back at least what the mode cost. Expected cost is cost × (1 − RTP): the average amount lost per round over the long run.
| Mode | Type | Cost | RTP | Max win | Max win odds | Pays anything | Returns the cost | Expected cost per round | |
|---|---|---|---|---|---|---|---|---|---|
| Base | Base spin | 1.00× | 96.70% | 20,000× | 1 in 2,857,171 | 1 in 3.43 | 1 in 65 | 0.03× base | Simulate |
| Extra Chance | Boosted spin | 2.00× | 96.70% | 20,000× | 1 in 1,000,002 | 1 in 4.71 | 1 in 49 | 0.07× base | Simulate |
| Bonus | Bonus buy | 100× | 96.70% | 20,000× | 1 in 20,000 | – | 1 in 11 | 3.30× base | Simulate |
| Lucky Spin | Bonus buy | 100× | 96.70% | 20,000× | 1 in 20,000 | 1 in 1.33 | 1 in 9.01 | 3.30× base | Simulate |
| Super Bonus | Bonus buy | 200× | 96.70% | 20,000× | 1 in 10,000 | – | 1 in 10 | 6.60× base | Simulate |
| Mysterybonus | Bonus buy | 250× | 96.69% | 20,000× | 1 in 8,001 | – | 1 in 5.97 | 8.28× base | Simulate |
Work out the cost of Book of Luck bonus buys at your bet size
Version history
Base-mode RTP per published math version. Older versions stay public in the fairness API, so changes can be checked.
| Version | Base RTP | |
|---|---|---|
| v9 | 96.700% | Active |
| v8 | 96.700% |
Frequently asked
What is the RTP of Book of Luck?
Base spins return 96.70% of the amount wagered over the long run, from the published outcome table for version 9. Its bonus buys return between 96.69% and 96.70%.
What is the max win in Book of Luck and how likely is it?
The top payout is 20,000× the base bet. On a base spin it lands 1 in 2,857,171 spins. In the Bonus buy (100×) 20,000× lands 1 in 20,000 buys.
Does Book of Luck have a bonus buy, and what does it cost?
Yes, 4 buy modes. Bonus: 100× the base bet, 96.70% RTP, an expected cost of 3.30× the base bet per buy. Lucky Spin: 100× the base bet, 96.70% RTP, an expected cost of 3.30× the base bet per buy. Super Bonus: 200× the base bet, 96.70% RTP, an expected cost of 6.60× the base bet per buy. Mysterybonus: 250× the base bet, 96.69% RTP, an expected cost of 8.28× the base bet per buy.
Is Book of Luck high or low volatility?
High. Its base-mode standard deviation is 46.6× the bet, which puts it in the highest third of Engine games. What volatility means.
Can I check that a result was fair?
Yes. Engine games use provably fair seeds. Once your server seed is revealed you can replay any round against the published outcome table. See how to verify a result.
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