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RTP is short for “Return To Player”. Although it’s commonly associated with slots, RTP is one of the most useful all-round casino metrics, as it helps measure the fairness and profitability of games.
But despite its ubiquity, the term remains widely misunderstood. So let’s clear up the confusion once and for all, by really digging into what RTP actually means.
RTP Definition
As I mentioned, RTP is an acronym that stands for “Return To Player”. Expressed as a percentage, it’s a figure that simply tracks how much is paid out, compared to the total stake.
For example, imagine you put £100 into a slot machine and play £1 per spin. You end up with £95 from your £100 stake, so you lost £5 overall.
It’s not hard to calculate that £95 from £100 worth of bets is an actual Return To Player rate of 95%.
Casinos use RTP, among other metrics, to track profitability. If players wagered £812,000 in a month, and the house paid £720,000 out in prizes, here’s the actual RTP:
(720,000 / 812,000) x 100 = 88.67%
Theoretical RTP
You’re probably more familiar with RTP in a theoretical sense. Pretty much every slot review ever written indicates the game’s theoretical RTP, as certified by some independent software testing house.
This value is used as a marketing tool for casinos and game developers, while giving players a sense of fairness. After all, one interpretation of high RTPs suggests you’ll win more – or at least lose less – in the long run.
The widely-accepted “average” for online slots is 96%, and we know slots will never pay more than they take in. As such, a figure of 96% to 100% is considered high, while anything below 96% is low.
House Edge
You may also have heard the term “house edge”, which is directly linked to RTP. But what’s the difference?
House edge indicates the mathematical advantage given to the game operator, whereas the RTP focuses on the player. They’re just two sides of the same coin, really.
If the RTP of a slot is 96%, the house edge must be 4%. When £96 is paid back for every £100 taken in, £4 is obviously retained by the house.
Random vs Compensated Control
How can a game that’s completely random be set to pay a fixed long-term figure? This is a great question, and one that’s often asked by newcomers.
There are two mechanisms to achieve this.
Compensated Control
The first is to use software that constantly checks results and fine tunes the odds or payouts to manipulate the payout. Since the machine knows what it’s supposed to pay, due to its preset theoretical RTP, and what’s been won already, it can tweak things as it goes.
If it’s paying too little, it might adjust the probability of landing a win to nudge the actual RTP upwards. It could also potentially increase the size of a payout in the forthcoming spins.
There are several reasons for a developer to take this approach. Controlling volatility is one, ensuring the player has an enjoyable experience. But some games permit complex strategies, and a range of potential outcomes. This makes it hard to reach a fixed RTP without some form of compensatory control.
Random Control
Alternatively, the game could be totally random, with the RTP baked into the mechanics. European roulette is a great example of this, with its famous 2.70% house edge – or 97.30% RTP, if you prefer.
Cover all 37 numbers with a £1 bet and see what happens. You’re guaranteed to win, but the bet only pays 35 to 1. That’s a £36 return on your £37 stake.
(36 / 37) * 100 = 97.30%
That’s all well and good, but a slot machine is nothing like a roulette wheel. How do slots control the RTP? Well, they might look different, but they’re not so dissimilar when you get into the underlying mechanics.
Slots and Random Control
Let’s create a simple three-reel slot machine to illustrate how it all works.
Our theoretical game has a fixed stake of £1 per play and a single winning payline. Each reel contains eight different symbols, meaning 512 permutations: 8 x 8 x 8 = 512.
Six symbols per reel pay a prize, but only for matching exactly three on the payline. Two symbols per reel are worthless, guaranteeing a loss.
There are two of each low-paying symbol – cherries and lemons – per reel. That means 2 x 2 x 2 = 8 opportunities to win. Two higher-paying symbols – the bell and horseshoe – feature once per reel, meaning just one winning combination each.
The table below summarises all of this, including the prize for each winning combination:
| Reel 1 | Reel 2 | Reel 3 | Per Reel | Prize | Wins | Return |
| Horseshoe | Horseshoe | Horseshoe | 1 | £100 | 1 | £100 |
| Bell | Bell | Bell | 1 | £75 | 1 | £75 |
| Lemon | Lemon | Lemon | 2 | £25 | 8 | £200 |
| Cherry | Cherry | Cherry | 2 | £15 | 8 | £120 |
| 18 | £495 |
Calculating the Theoretical RTP
As you can see, only 18 of the 512 permutations produce a win. The remaining 494 return nothing.
If we spun the reels 512 times, it would cost £512. And if we experienced one of every possible result, as we’d expect to in theory, we’d be paid £495:
- 1x £100
- 1x £75
- 8x £25
- 8x £15
- 494x £0
The theoretical return to player, therefore, is 96.68%:
(495 / 512) * 100 = 96.68%
Theory and Practice
Remember, a game’s RTP is pure theory. The only guarantee is that if you played to infinity – or at least made an enormous number of bets – the percentage return would eventually settle at the theoretical figure.
Every individual outcome remains random. You could win back-to-back jackpots, or you could lose for 50 consecutive turns. A high RTP doesn’t mean a high short-term payout.
This is where people commonly confuse RTP with volatility. So let’s talk about that distinct, but related concept now.
Volatility and Variance
If the RTP of a game tells us what it pays, volatility indicates how it will pay. Volatility is sometimes called variance, but it’s the same thing.
In short, a highly volatile game is more likely to produce a longer losing streak, but bigger prizes than average. With low-volatility games, you’ll probably win a lot more frequently, but those individual payouts tend to be much smaller.
Slots Example
Imagine two extreme examples:
In Slot A, you play 100 turns at £1 each, for a total stake of £100. During that 100 spin session, you lost 99 times, but a single spin paid £96.
You then did the same with Slot B. This time, you lost on 68 spins, winning exactly £3 on the other 32. Your total returns were also £96.
I think you already get my point. Both games paid £96 from a £100 stake – an RTP of 96%. But Slot A made you endure long dry spells, paying large prizes, while Slot B drip fed smaller wins on a steady basis.
Both have identical RTP rates, but Slot A is high on the volatility scale, while Slot B is a low-volatility game.
Our Theoretical Game
Remember the slot machine we built earlier? We can calculate its volatility just as easily as the RTP. Well, we can actually work out the hit rate, which is a more specific measurement of the same concept.
There were 18 winning permutations from a possible 512. That’s a theoretical hit frequency of 3.52%.
(18 / 512) * 100 = 3.52%
This suggests fairly high volatility. Players should expect long losing streaks, but comparatively large prizes whenever they win.
Unfortunately, there’s no uniformity when it comes to qualifying volatility – every developer and reviewer has its own scale. Some might call this “medium-high”, while others may simply say “high”.
RTP and Regulation
How do players know that the theoretical RTP is real? After all, most of us don’t have the bankroll to play millions of spins and find out the hard way.
This is why it’s important to play at regulated casinos. With a reputable gaming authority overseeing both the operator and the game developer, we can take it on trust that the RTP, volatility and other stats have been independently verified.
Tests are carried out by third-parties, including well-known compliance agencies like GLI, eCOGRA and iTech Labs. They simulate large numbers of spins to confirm that underlying RNG (Random Number Generator) software is completely legit.
Common RTP Misconceptions
To wrap up this guide to RTP, let’s bust a few myths concerning RTP.
1– This game is due to pay
RTP indicates how much the game returns in theory, over a long period of time. It’s nothing more than an average of every individual result, forever. Losing over 100, or even 500 slot spins, is completely meaningless.
You need to track hundreds of thousands, if not millions of spins, for this theory to even be close to correct. Believing anything else is succumbing to the famous gambler’s fallacy.
Even if the game is one with compensated control, outcomes are still random. The probabilities or prizes may have been tweaked in real time, but you could still hit a long losing run.
2– Demo games have higher RTPs
There’s a widespread belief among cynics that free-to-play demo games beef up the RTP to make players think it’s easy to win. Then, when you play for real money, you’ll lose.
It’s just not true. The theoretical payout is built into the game’s mechanics. Look at the roulette example from earlier. How can you “turn up” the RTP of that game?
The only way to increase the overall RTP is to increase the individual payouts, like paying 36 to 1 instead of 35.
3– Higher RTP Means Better Odds
A game’s RTP is just one factor in how it pays. Volatility plays a big role too, along with things like the maximum potential payout and bonus frequency.
As I explained, highly volatile games are prone to making you suffer losing streaks. Nothing changes just because the RTP is high.
Besides, whether it’s 79% or 99%, you can just as easily experience a winning session as a losing one – outcomes are completely random.
