BOOK slot: RTP and max win
BOOK is a medium-volatility slot by Helio labs on Stake Engine, released 17 Sep 2026. Its base game returns 96.00%, below the median Engine slot (96.02%). The top payout is 20,000× the bet, bigger than 59% of Engine slots; from a base spin it lands about once every 7,643,312 spins. It has 5 bonus buys priced at 75× to 500× the bet; the best returns 96.00%, so each buy costs 3.00× the bet on average over the long run. It is the No. 2095 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 v3. "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× | 96.00% | 20,000× | 1 in 7,643,312 | 1 in 5.00 | 1 in 12 | 0.04× base | Simulate |
| Enhancer | Boosted spin | 3.00× | 96.00% | 20,000× | 1 in 2,038,967 | 1 in 7.41 | 1 in 23 | 0.12× base | Simulate |
| Super Enhancer | Boosted spin | 10× | 96.00% | 20,000× | 1 in 1,405,152 | 1 in 13 | 1 in 27 | 0.40× base | Simulate |
| Feature Spin | Bonus buy | 75× | 96.00% | 20,000× | 1 in 50,000 | – | 1 in 3.52 | 3.00× base | Simulate |
| Regular | Bonus buy | 100× | 96.00% | 20,000× | 1 in 50,000 | every round | 1 in 1.69 | 4.00× base | Simulate |
| Mystery | Bonus buy | 250× | 96.00% | 20,000× | 1 in 62,500 | 1 in 2.86 | 1 in 4.37 | 10.00× base | Simulate |
| Super | Bonus buy | 250× | 96.00% | 20,000× | 1 in 50,000 | every round | 1 in 1.93 | 10.00× base | Simulate |
| Epic | Bonus buy | 500× | 96.00% | 20,000× | 1 in 50,000 | – | 1 in 40 | 20.00× base | Simulate |
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 | |
|---|---|---|
| v3 | 96.000% | Active |
Frequently asked
What is the RTP of BOOK?
Base spins return 96.00% of the amount wagered over the long run, from the published outcome table for version 3. All 5 of its bonus buys return 96.00%.
What is the max win in BOOK and how likely is it?
The top payout is 20,000× the base bet. On a base spin it lands 1 in 7,643,312 spins. In the Feature Spin buy (75×) 20,000× lands 1 in 50,000 buys.
Does BOOK have a bonus buy, and what does it cost?
Yes, 5 buy modes. Feature Spin: 75× the base bet, 96.00% RTP, an expected cost of 3.00× the base bet per buy. Regular: 100× the base bet, 96.00% RTP, an expected cost of 4.00× the base bet per buy. Mystery: 250× the base bet, 96.00% RTP, an expected cost of 10.00× the base bet per buy. Super: 250× the base bet, 96.00% RTP, an expected cost of 10.00× the base bet per buy. Epic: 500× the base bet, 96.00% RTP, an expected cost of 20.00× the base bet per buy.
Is BOOK high or low volatility?
Medium. Its base-mode standard deviation is 20.4× the bet, which puts it in the middle 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.
Slots with similar math to BOOK
Matched on volatility, max win, RTP and whether there's a bonus buy. Not on theme.
SNOWBALL'S CHANCEDarkbyte RTP96.00%Max win20,000×Volatility
SERIAL WINNERSLEGENDIA LABS RTP96.00%Max win20,000×Volatility
KAIJU DISTRICTSAVAGE GAMING RTP96.00%Max win20,000×Volatility
Hostile TakeoverSpinova RTP96.00%Max win20,000×Volatility
WASH.EXEArctic RTP96.00%Max win20,000×Volatility
Chad VS WaifuRenkler Studios RTP96.00%Max win20,000×Volatility