Understanding slot machine house edge

Understanding slot machine house edge
November 17, 2021

It’s no news that casinos make money from players’ losses, and the house edge represents a constant tipping point in their favor. The price of a game is determined by the expected house edge, not by the cost of the bet. A 5% house edge on a $10 bet means that, in the long run, a game will return $0.50 to the casino for each $10 bet. Naturally, a 10% house edge or higher would be more expensive to play overtime.

Finding the house edge in slots

Slots are usually referred to as having payout percentages or, better still, RTP (Return to Player). However, it’s easy to decipher the house edge from the RTP, as both rates should add up to 100%. For instance, a slot with a 96% RTP has a 4% house edge. As such, you could think of RTP as the reverse house edge.

Different slot games have different house edges, which usually range from less than 1% to 10%. An example of a high paying slot is Ugga Bugga by Playtech featuring a 99.07% RTP. Lower paying ones includethe 6×6-grid Tropicool slot by ELK Studio which offers a 95% payback rate. You can find the best casinos to play these games at PayPal Casino.

Why slots have a higher house edge than other casino games

A casino’s stream of income is usually revenue from slots. All casino games have an element of chance, but none are as random as slot gameplay.

For instance, with blackjack (0.5% house edge), each card you are dealt is a chance event. At the same time, the move you choose to make with it (stand, hit, double down, etc.) is your choice and plays a significant part in the outcome.

Another example is roulette (2.7%; European, 5.26%; American). Although roulette is a non-skill game just like slots, it features better odds. Considering a bet on Black/Red, there are only two possible outcomes, so you have roughly equal chances of winning or losing.

It’s easy to calculate the house edge in games like blackjack or roulette. However, slots function on a math model that’s been embedded by the game developer. The math behind the game guides the expected payback, and there are tons of calculations and codes involved. As such, the house edge on slots is a lot harder to decipher.

How do slots gain the house edge?

Several statistics play to the workings of a slot machine, most notably, volatility (variance), paylines, and jackpots. All these elements can help determine where the house edge lies. Volatility indicates how often and how much you can win on a spin, and the number of paylines also impacts your chances of winning. Slots with a progressive jackpot will have a percentage of the house edge allotted to the pot, thereby lessening the payback rate on regular gameplay.

Having an idea of the volatility, payline, and other slot statistics will give you an idea of the house edge. It can also help you decide the best game to play as these elements influence the gameplay experience.


Ultimately, the house edge is a long-run concept, so the casino will not literally win over every bet that every single player makes. Lucky players can turn up a hefty payout and, in a sense, beat the casino. However, slots are designed to return a certain amount back to the casino, so if not you,someone else will be paying the price.