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Welcome to the Gratidues. We are a couple of regular guys that enjoy playing casino online. Read our blogposts for Casino information and big gambling wins!

How Casinos Make Money

Let’s say that we are playing a game of flip the coin, and because we’re fun people we’re also betting on it.

 

If we bet £1 a throw.

  • I win £1 and you lose £1 if the coin comes up heads.
  • You win £1 and I lose £1 if the coin comes up tails.

That is what we call a fair game.

There is risk – we could play 100 flips and I might lose money, or I might win money. But either way, it is just down to luck. Statistically, I am not more likely to win than to lose.

There is a 50% chance of me winning each throw, and a 50% chance of me losing each throw.

That is not what it is like in a casino.

Let’s change the rules slightly:

  • I win £1 and you lose £1 if the coin comes up heads.
  • You win £1.10 and I lose £1.10 if the coin comes up tails.

That is not a fair a game.

There is still risk – we could play 100 flips and I might make money. But I am more likely to lose.

I have a 50% chance of winning £1 and a 50% chance of losing £1.1.

That means that on each coin toss I expect to lose 5p.

We use this word “expect” a lot when it comes to making money from casino bonuses. It basically means the average profit from all possible outcomes.

Here is a very simple tree showing you how we worked out that expected loss of 5p.

Please take a second to make sure that you fully understand why that is. If you can get your head round it then everything else should quickly fall into place.

Now let’s turn that expected loss into a percentage of the amount we staked. That number becomes what is called the house edge.

So the house edge is 5% (0.05 means the same thing as 5%).

That means that in the long term I expect to lose 5% of whatever I bet. If we play 1,000 flips, I will have bet £1,000 and expect to lose £50 (5% of £1,000).

There’s that word expect again. It doesn’t mean I will definitely lose £50 (in fact I may be lucky and make money), but it means that on average I will lose £50.

Now we get a bit more complicated. The longer I play, the more likely I am to lose money. I am not going to explain the maths here (email me if you want to know) but, but over 1 coin flip my chance of walking away with a profit is 50%. The coin can either come up heads or tails. Over 100 coin flips my chance of making a profit has dropped to 31.7%, that’s almost a 1/3rd chance which still is quite high. I might decide that I’m feeling especially lucky and take that 1/3rd chance. But over 6,000 coin flips my chance of leaving with a profit drops only 1%.

That is how a casino makes money. If there are 60 people playing at your casino and each plays the coin flip game 100 times, then each person has a 31.7% chance of leaving with a profit. But as the casino is playing 6,000 total flips it only has a 1% chance of not making a profit overall. A pretty clever business model.

Now you can’t actually play our coin flip game in a casino so let’s apply this concept to two real casino games.

Roulette. Is a very basic game which almost everyone understands.

 

There are 36 numbers not including the zero. Of those 36 – 18 are red and 18 are black. The number zero is not red or black. Each time the wheel spins there is an equal chance that the ball will land on any of the numbers 0 – 36.

Bets

If you bet on red and it comes up, you win your stake back. So a £1 bet would win £1.

There is an 18 out of 37 chance of a red colour coming up. That means that you have a 48.6% chance of winning, and a 51.4% chance of losing.