Every certified slot publishes its own rules, usually behind a small "i" in the corner, and almost nobody opens it. It is the only place the game tells you the truth about itself.
What is in there
- Symbol values — what each symbol pays for three, four or five of a kind, usually expressed as a multiple of the stake or of the line bet. Check which, because the difference is large.
- Payline diagrams — the exact paths that count, if the game uses lines rather than ways.
- Feature rules — what triggers a bonus, how many spins it awards, whether it can retrigger, and what the modifier is.
- Wild behaviour — what it substitutes for and, importantly, what it does not.
- RTP — the stated return, where the market requires it to be published.
- Maximum win — capped in most modern games, often at a multiple of stake. A cap changes the shape of the whole game.
The three things worth checking before you play
- Are the values in stake or line bet? A symbol paying "50" means something very different depending on which, and the paytable will say.
- Does the wild substitute for the scatter? Usually not. This is the most common source of "that should have paid".
- Is there a win cap? In a high-volatility game the cap is often where the headline return actually lives.
What a paytable will not tell you
It will not give you symbol probabilities. The weighting behind the reels is part of the game's certified mathematics and is not published, which is why you cannot work out the odds by counting symbols on screen. What the paytable gives you is the rules; the distribution stays behind the curtain.
A note on social games
A social casino is under no obligation to publish RTP at all, and many do not. That is not a scandal, because nothing of value is at stake, but it does mean the paytable of a free game tells you about its rules rather than its economics.