Only a handful of slots return 99% or more. Here are the three we review, how each one gets there, and the famous 99% figures that come with conditions.
Three slots in our catalogue return 99% or more: Playtech’s Ugga Bugga at 99.07%, and NetEnt’s Mega Joker and Relax Gaming’s Book of 99, both at 99.00%. That leaves the house an edge of about 1%, against roughly 4% on a typical slot. The details matter, though: Ugga Bugga caps at 1,000x the line bet, and Mega Joker reaches its 99% only through its Supermeter mode.
The Three 99% Slots We Review
| Slot | Studio | RTP | Volatility | What Sets It Apart |
|---|---|---|---|---|
| Ugga Bugga | Playtech | 99.07% | Low | You choose which symbols to hold for a second spin |
| Book of 99 | Relax Gaming | 99.00% | Medium to high | A modern book-style free-spins game |
| Mega Joker | NetEnt | 99.00% | High | A classic fruit machine with a progressive jackpot |
Ugga Bugga
Ugga Bugga looks nothing like a modern slot. Its grid is three columns and ten rows, split into two blocks, and each spin comes in two stages: after the first, you pick the symbols worth keeping and spin the rest again. There are 10 fixed lines, no free spins and no bonus buy, so all of the return comes from the base game. Low volatility makes it the steadiest of the three, with a top win to match.
Book of 99
Relax Gaming built Book of 99 around its return, and it is the most modern game of the group: a Greek-mythology book slot on 5×3 reels with 10 fixed lines. It adds a collection meter for its book symbols to the usual free spins with an expanding symbol, and four Greek heroes are among the symbols that can expand. Relax gives the top win as 5,000x the stake. The game comes in one version only, so every casino that carries it runs the 99%.
Mega Joker
Mega Joker is NetEnt’s three-reel fruit machine with two modes, one of the classics on our 5 payline slots page. The base game collects modest wins, which can be carried up into the Supermeter, and that mode at maximum coin is where the 99% comes from; the base game played on its own returns far less. NetEnt puts its hit frequency at 17%, so fewer than one spin in five pays anything. A Mystery Win feature and a progressive jackpot sit on top, and the game runs high volatility.
What the 99% Slots Have in Common
Most of the tier is plain, older design, fruit machines above all, with few features and modest caps. The return alone does not decide a game’s top win or how hard it swings, though. Book of 99 keeps a book-style bonus and a 5,000x ceiling, and it swings harder than Ugga Bugga.
99% Figures That Come With Conditions
Several games appear on 99% lists with a figure that holds only some of the time. Playtech’s Goblin’s Cave is listed at 99.32%, but that applies only at maximum coins; with fewer coins it returns nearer 94.5%, and its top win is small. Barcrest’s Ooh Aah Dracula returns 96% in its normal game and 99% only in its Big Bet mode, where you pay a fixed price for five enhanced spins, and Barcrest’s Monopoly Big Event uses the same kind of mode. UK casinos do not offer paid bonus features of that kind, so UK players get the 96% game. NetEnt’s Jackpot 6000, at 98.90%, sits just under the line.
Studios also let casinos choose a lower-RTP version of many games, so a slot listed at 99% can run lower at a particular casino. To see which version a casino uses, open the game’s paytable or rules page there.
