How slot machines work

A slot machine is the easiest game in the city to play and the easiest to misread. You choose a bet and press a button; nothing you do after that changes the result. So there is no strategy to learn here — but there is a lot to understand, because almost everything people believe about slots comes from reading patterns into random results.

These guides take the three machines of the Treasury of Ra apart. We did not copy textbook numbers: we took the real reel strips and paytables from the game’s code and counted. Sevens of Ra has 64,000 possible reel positions, Book of Thoth 55,566,000 and Treasures of Horus 87,852,960 — few enough that a computer can go through every single one. What could not be listed outright, like a chain of free spins, we worked out by formula and checked by playing millions of simulated rounds with the same code the server runs.

• RTP and volatility — why a machine that returns 95% can empty a purse in 200 spins, and a session simulator to see it happen.
• Free spins — how the expanding symbol of Book of Thoth works, and why the symbol everyone hopes for pays least on average.
• Hold & Win — respins, sticky scarabs and jackpots, with a bonus you can play right on the page.
• How results are made — the random number generator, the spin settled before the reels stop, near misses and the usual myths.

All three machines pay back about 95% over the long run, so every 100 debens you bet cost about 5 on average. And any session you can actually play is too short for that average to show: on Sevens of Ra it takes roughly 13,000 spins before the house edge outweighs ordinary luck, on Book of Thoth more than twice as many. Play for the fun of the reels, set a limit, and treat a big win as luck rather than a sign.