Book of Cats

Provider

BGaming

RTP

96.99%

Volatility

Very high

Maximum win

8,202x

Layout

5x3, 10 lines

Released

8 July 2020

Book of Cats has the highest published return of any BGaming slot covered on this site at 96.99%, and it is also classified very high volatility. If you want a single game that demonstrates why RTP alone tells you almost nothing about how a slot feels to play, this is it.

What "book" games are

This is a Book of Ra descendant, and the format is worth understanding because there are dozens of them and they all work the same way:

1. A book symbol acts as both scatter and wild
2. Three books trigger ten free spins
3. Before the round starts, one symbol is chosen at random to become the expanding symbol
4. During the round, that symbol expands to fill its whole reel and pays from any position

The entire game hinges on step three. Draw a high-paying symbol and the round can be enormous. Draw a low-paying one and ten free spins produce very little. That single random draw, made once per feature, is the source of nearly all the variance.

Why 96.99% and very high volatility coexist

They coexist precisely because of the expanding-symbol draw.

The return is calculated across every possible outcome of that draw, weighted by probability. Most draws produce modest rounds. A small proportion produce very large ones. Average them and you get 96.99% — an excellent figure. Experience them one at a time and you get long stretches of disappointment punctuated rarely by something substantial.

Ten paylines rather than the twenty or twenty-five typical of modern releases sharpens this further. Fewer lines means fewer small wins in the base game, which means less to cushion the wait.

The ceiling

8,202x. Note the precision. Numbers like this are not marketing rounding — they are the actual computed maximum from the game's maths, usually the top-paying symbol expanded across all reels with retriggers. When a studio publishes 8,202x rather than "up to 8,000x", that is a good sign about how it handles its data generally, and BGaming is consistent about it across its catalogue.

Retriggers

The free spins retrigger. Landing three more books during the round adds another ten spins with the same expanding symbol still in play.

This is where the top-end results come from. A high-value expanding symbol plus a retrigger is a fundamentally different event from the same symbol without one, and it is rare enough that planning around it is planning around something you will very likely never see.

Gamble and buy features

A gamble round is available on wins, and a buy feature where jurisdiction permits.

The gamble round is worth one specific note: it is typically a near-even-money proposition, which means it is closer to fair than the slot itself. It does not improve your expected return over a session, but unlike the slot it does not materially worsen it either. That is an unusual thing to be able to say and it is specific to this feature type, not general advice.

Who it suits

Someone who understands the book format and specifically wants the expanding-symbol lottery. The high return means that over a long horizon this is among the better-priced games available anywhere, not just in BGaming's catalogue.

It does not suit anyone who read "96.99% RTP" and expected a comfortable ride. The return is real and the volatility is real, and the second one is what you will actually experience.

Also on this site

• Book of Dead and Legacy of Dead — Play'n GO's takes on the same format
• Dig Dig Digger — BGaming's other expanding-symbol game, two full points lower in return
• Aztec Magic Megaways — comparable return and volatility, different engine

---

Source: BGaming's published game data. Reviewed 29 August 2026. A published "hit rate" value has been omitted — BGaming does not define the metric.

Reviewed by SlotzKilla Editorial · Published 29 August 2026 · Last updated 29 August 2026 · How we source figures