Modern day casino slot machines are computerized and come with many variations. There is a random number generator (RNG) in the slot machine that continuously generates random numbers. The random number generated at the moment when the customer presses the ‘play’ button or downs the lever determines his money ‘payout’. So, the amount paid depends on the exact time of playing.

Jurisdiction laws determine the percentage of wager money that is paid out as winnings from the casino slot machines. It varies from city to city and is in general between 82 to 98% of the wager money. This pay out percentage is built into the software itself – the software has to be modified if this percentage is to be changed.