Book of 99
- Its RTP is 2.75 percentage points above the Relax Gaming median.
- On published RTP it beats 99.9% of the 2,808 games in our database.
- Its RTP sits 2.8 percentage points above the database median.
- 67% of its key figures carry an independent corroborating source.
The full record
Every field the provider publishes. A dash means the figure isn't published — we don't guess.
How the game works
The documented mechanics, from the game's own paytable and rules screen.
A 5×3 grid running 10 lines. Wins pay left to right on the published paylines.
Relax Gaming rates it high volatility — expect longer gaps between bigger hits.
The advertised ceiling is 12,075× your stake — a theoretical maximum, reached rarely.
Features on record
The features the provider lists for this game. Each links to every slot in the database that shares it.
Where each figure comes from
Per key field: the source, the confidence, and when we last checked. We flag anything unverified instead of presenting it as certified.
Our read on the numbers
At its default 99.0%, Book of 99 sits 2.52 points above the 96.48% average of the 20 Relax Gaming titles we track, and it beats 99.9% of the 2,808-slot database. That makes the default version an ordinary-to-fair return for the studio.
Book of 99 vs the Relax Gaming catalogue
How this title sits inside the 20 Relax Gaming slots in our database.
Book of 99 (99.0%) against the Relax Gaming median (96.25%). See the full Relax Gaming catalogue →
If you like this one
Closest matches by feature overlap and RTP — every row links to its own full record.
 Marching LegionsRelax Gaming | 98.12% | 10,000× | Relax Gaming | 2020 | ||
 Kluster Krystals MegaclustersRelax Gaming | 96.49% | 9,921× | Relax Gaming | 2021 | ||
| Wild ChapoRelax Gaming | 96.36% | 10,000× | Relax Gaming | 2021 | ||
| Snake ArenaRelax Gaming | 96.25% | 2,759× | Relax Gaming | 2020 | ||
 Temple TumbleRelax Gaming | 96.25% | 7,767× | Relax Gaming | 2019 | ||
 Money TrainRelax Gaming | 96.2% | 20,000× | Relax Gaming | 2019 |
What we've changed
Every recorded change to this game's data. No entry is invented — this is the provenance log.
- 11 Jul 2026RTP corroborated against slot.report (independent database); values agree.
- 11 Jul 2026Volatility rating corroborated against slot.report.
- 11 Jul 2026Book of 99 imported into the RTPBoss dataset with provider-published figures.
Where to play
Top-scored crypto casinos carrying most major providers. Catalog coverage varies — confirm the game is live before depositing.
18+ · Rankings use documented criteria, not commercial terms · Play responsibly
Common questions
What is the RTP of Book of 99?
Book of 99 by Relax Gaming has a published RTP of 99.0%, a house edge of 1%.
How volatile is Book of 99?
Relax Gaming rates Book of 99 as high volatility. Individual sessions can swing far from the published RTP; the RTP is a long-run average, not a per-session expectation.
What is the max win in Book of 99?
The advertised ceiling is 12,075× the stake. That is a theoretical maximum, not a typical or expected outcome.
RTP is a long-run average, never a guarantee for any session. Slots are entertainment, not income. 18+ only — set a budget you can afford to lose and never chase losses.