How Are Online Slot Machine Payout Percentages Calculated?

Online Slot Machine

When you hit the spin button in an online slot machine, the outcome/result is pre-determined by a frequently tested Random Number Generator (RNG). RNGs are designed to produce fair and realistic results with no discernible pattern.

Online slot machine payout percentage rates are calculated in a number of ways.

For example, internationally accredited online casino testing agencies, such as eCOGRA (eCommerce Online Gambling Regulation and Assurance), use their software and systems to test the games over a certain period of time to reveal the average Return to Player Percentage (RTP%) payout rates for the games.

We can also tell the average payout rate by how much players spent on an online slot machine over a four-week period and how much that slot paid back in winnings. Let’s take a closer look at some examples of how this works.

What kind of payout rates should online slots have?

Most online slots from today’s well-established, market-leading online casino game development studios and software providers often have an average RTP% payout rate of around 93.00% to 98.00% or higher, which is pretty good, especially for the players.

Here’s an example:

If players all collectively spent £1,000,000 playing one particular online slot machine over four weeks, and those players received back, on average, £959,700, it means that slot machine had an average 95.97 RTP % payout rate for that period.

If those same players spent, say, £500,000 on a different online slot machine from another company and received £491,150 back in winnings over a four-week period, it means this game had an even higher average RTP% payout rate of 98.23%, and so on.

You can learn more about individual online casino game payout rates on the official 32Red Casino website, and you can also get the latest online casino, football, racing, and boxing news by visiting the online casino blog 32Red.

Ten online slot machine RTP% payout rates

We managed to obtain the payout rates for hundreds of famous online slot machines. Instead of listing them all, here are just ten examples for you, including the name of the game and the RTP % payout rate.
Online Slot Machine

  • John Hunter and the Book of Tut Respin by Pragmatic Play – 94.47%
  • Britain’s Got Talent Megaways online slot by Iron Dog Studios (exclusive) – 96.20%
  • Fishin’ Frenzy Megaways Jackpot King (the progressive jackpot version of a famous slot by Reel Time Gaming and Blueprint Gaming) – 94.50% +0.5%
  • 10,001 Nights Megaways online slot by Red Tiger Gaming – 93.16%
  • Absolootly Mad: Mega Moolah online slot by Triple Edge Studios and Games Global – 92.02%
  • Thai Flower Megaways online slot by Blueprint Gaming – 95.02%
  • Book of Atem WowPot online slot by All41 Studios and Games Global – 96.45%
  • Fairytale Legends: Red Riding Hood online slot by NetEnt – 96.30%
  • Jurassic World: Raptor Riches Jackpot online slot by Fortune Factory Studios and Games Global – 92.03% / Win Booster™ 92.04%%
  • Fishin’ Frenzy online slot by Reel Time Gaming and Blueprint Gaming – 96.12%

There are over 1,800 more online slot machines on the 32Red website, and they have the latest RTP % payout rates for all of their slots.

Do any slots have a 98.00% or higher RTP rate?

Yes. Many online slots have a 98.00% RTP rate or higher. Examples include the 1429 Uncharted Seas online slot by Thunderkick (98.60%), the Marching Legions online slot by Relax Gaming (98.12%), the Maya Gold online slot from IGT (98.44%), and the Money Cart online slot by Relax Gaming (98.00%)

Final note

Don’t forget, just because an online slot has a slightly higher percentage rate than another slot doesn’t necessarily mean you are guaranteed to win more. Although RNGs produce the outcomes, and some slots have higher average payout rates than others, it’s all still down to lady luck whether you win or not.


Hi, I'm Raj Hirvate & I am a Tech Blogger from India. I like to post about technology, gadgets, How-to, Errors and product reviews to the readers of my website. Apart from blogging i'm a big Anime fan I Love Watching Naruto, Jujutsu Kaisen, One piece, Death Note and any upcoming animes.

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