Gambling terms, explained straight

In British English, a slot machine is also called a fruit machine. The term may sometimes extend to other electronic games like video poker.

Slots & Gaming Machines

Slot machine

A slot machine is a reel-based gaming machine designed for gambling, where each outcome is determined by a random number generator.

Also called
Fruit machine, slot, jackpot machine 1
How it works
Generates random numbers per reel, maps to positions, stops reels. Result set at play initiation, spinning is display only. 2
Legal definition (Great Britain)
A machine 'designed or adapted for use by individuals to gamble'. 3

Key points

  • Outcome is determined by random numbers the moment you press spin; the reels are just for show. 2
  • In Great Britain, slot machines are legally defined as gaming machines under the Gambling Act 2005. 3
  • A progressive slot machine has a jackpot that grows with each bet until someone wins it.
  • A loose slot machine is one that pays out more frequently or at a higher percentage than average.
  • Slot machine tournaments are competitions where players compete for the highest score or most credits within a set time.

How a slot machine works

  1. You place a bet and press spin or pull the lever.
  2. The machine's random number generator selects a number for each reel instantly.
  3. Those numbers are mapped to reel positions, and the reels stop at those positions.
  4. If the symbols line up on a payline, you win according to the paytable.

Slot machine strategy

There is no strategy that can beat a slot machine because outcomes are random. However, you can manage your bankroll, choose machines with higher return-to-player percentages, and understand volatility. A common tip is to set a loss limit and stick to it.

Common questions

What is a progressive slot machine?

A progressive slot machine has a jackpot that increases each time a bet is placed, until a player hits the winning combination. The jackpot can be linked across multiple machines.

What are the odds of winning a slot machine?

The odds vary by machine and are determined by the random number generator and paytable. Casinos set the return-to-player percentage, typically between 85% and 98%.

What is a slot machine tournament?

A slot machine tournament is a competition where players spin on designated machines within a time limit, aiming to accumulate the most credits or highest score for prizes.

What is a loose slot machine?

A loose slot machine is one that pays out more frequently or has a higher return-to-player percentage than the casino average. Casinos may place them in high-traffic areas.

Where this term is used

Not the same as

  • Slot machine jackpot — the jackpot is the prize or top payout, not the machine itself
  • Slot machine reels — reels are the rotating display elements inside the machine, not the whole machine

Sources

  1. Gaming machine categories gamblingcommission.gov.uk Provides the regulatory definition of gaming machines in Great Britain and the term 'fruit machine'.
  2. Slot Machines wizardofodds.com Explains how slot machines work, including random number generation and display.
  3. Gaming machine - Gambling Act 2005 legislation.gov.uk Contains the legal definition of a gaming machine under the Gambling Act 2005.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.