Relax Gaming

Book of 99

RARE Slots Video Slots Mythology Action & Adventure Book Greece Ancient

Play Book of 99 slot by Relax Gaming for free in demo mode! Explore RTP, bonus rounds, and key features before playing for real.

Only <0.01% of slots combine 10 Paylines and High Rtp Slots.

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SlotRanker Score

/ 99

05099

The SlotRanker Score is calculated from the visible data below. It is not affected by affiliate deals or paid placement.

How this score is built

RTP

99%

return to player

Volatility

High volatility

variance

Max win

12,075×

top multiplier

Min bet

$0.10

per spin

Reels

10 lines

Player rating

4.7 ★

15 votes

DEMO Play free, no signup

Relax Gaming

4.7 / 5

15 ratings

User ratings are shown separately from the Slot Score unless stated otherwise.

Five weighted signals shape the composite. Four context signals refine ties. See how we rate for the full methodology.

Payouts & RTP10/10

RTP 99% → 10.0/10

Volatility9/10

high → 9.0/10

Win Potential8.2/10

x12075.00 (12075×) → 8.2/10

Features8/10

13 features → 8.0/10

Game Mechanics4.2/10

f=13 r=5 p=10 → 4.2/10

Context signals (tie-breakers)

Layout6/10

5x3 → 6.0/10

Bet Flexibility6/10

0.1–100 (×1000) → 6.0/10

Provider Reputation7.4/10

provider avg 7.4 → 7.4/10

Popularity7.5/10

search demand p76 + proxy blend (70/30) → 7.5/10

Popularity blends real player search demand (~30 markets) with a catalogue-derived proxy; games without measurable search demand use the proxy alone. Not live play telemetry.

Cite this score

SlotRanker Score: 79 — Book of 99 by Relax Gaming

https://slotranker.com/relax-gaming/book-of-99#score

How to cite

Spec sheet

Book of 99 at a glance.

Identity

Slot nameBook of 99

StudioRelax Gaming

Released5/4/2021

Math

SlotRanker Score79

RTP99%

VolatilityHigh volatility

Max win12,075×

Bet range$0.10 – $100.00

Player rating4.7 / 5 · 15 votes

Format

Reels5

Paylines10

Layout5x3

Features

Themes

Expected average based on this slot's 99% RTP — individual sessions vary with volatility.

Bet per spin

Spins per hour400

Session length (hours)

Cost per hour$0.40

Cost per session$0.40

Estimate only, for entertainment purposes — treat gambling as entertainment, not a way to make money, and set a budget you can afford to lose.

How long could a bankroll last on Book of 99? We simulate thousands of sessions from this game's published RTP and volatility — the long-run math, not a prediction of your next spin.

Bankroll ($)Bet per spin ($)Speed

Volatility tier: High

Running simulation…

How this works

Each simulated spin either misses or returns a win drawn from a log-normal distribution, with the hit rate and spread set by the slot's volatility tier (High). The model is calibrated so the average return equals this slot's published RTP (99.00%), with wins capped at its top multiplier (12,075×).

This is a simplified, parametric model of the game's math — not its real paytable. It exists to make the house edge visible over many sessions, so the numbers above are averages across thousands of runs, never a forecast of one.

This is math, not a prediction. Real sessions vary wildly, and no strategy changes a game's built-in house edge. Play for fun, set limits, and never bet more than you can afford to lose.

Compare Book of 99 with other games

	Book of 99 Score 79This game	Pandora’s Treasure Score 75	Book of Helios Score 66	Book of Trojan Tales Score 56	Serpentina Score 91
Identity
Studio	Relax Gaming	NetEnt	Betsoft	Spinomenal	Massive Studios
Released	5/4/2021	5/2/2024	6/16/2022	6/17/2024	3/20/2025
Math
RTP	99%	96.13%	95.58%	—	96.53%
Volatility	High volatility	Medium volatility	High volatility	—	High volatility
Max win	12,075×	10,368×	20,168×	5,000×	30,000×
Format
Reels	5	6	5	5	7
Layout	5x3	6x4	5x3	5x3	7x7
Paylines	10	4096	10	10	—
Min bet	0.10	0.10	0.10	0.10	0.10
Max bet	100.00	40.00	10.00	100.00	100.00
Features
Progressive	—	—	—	—	—
Wild symbol	✓	—	✓	✓	✓
Free spins	✓	✓	✓	✓	✓
Scatter symbol	✓	✓	✓	✓	✓
Multiplier	—	—	✓	—	✓
Bonus game	—	—	—	—	—
Respins	—	—	—	—	—

Every number is shown as a delta against Book of 99.

Comparing against

Book of 99

Relax Gaming

RTP

99%

Max win

12,075×

Score

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