When you are observing a Slots machine’s payout table, you would notice that they produce different payouts for different coins played. A simple combination may let you win 10 coins if you play with a single coin, 20 coins if you play two, and of course 30 coins if you play three. The difference between the three payout tables is cause by multiplier.
Multiplier is basically a certain constant number that influence the payout table for each number of lines being played. The usual multiplayer is x2, which means you will proportionally get more payouts with more lines. There are also Slots machines providing bigger payouts when you play more lines, such as by using x8 as the multiplayer, which makes playing more lines seems a lot more profitable.
Aside from multiplier, you can also find bonus multiplier used in Slots machines. If you notice the jackpot being higher than the actual multiplied payout ratio that is because the machine adds bonus multiplier to it. Triple 7’s may give you a rewarding 1000 coins when you play a single line, 2000 coins when you play two lines, and a whopping 10000 coins if you play all the lines. Notice the difference?
Knowing multiplier and bonus multiplier will help you decide which machine you should choose quite easily. Remember that you would have to play all lines, usually three if you are playing 3-reel Slots machines, to qualify for the jackpot. Other than that, you can use multiplier to see if betting on more lines is actually worth it.