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22 June 2024

The Maths Behind Accumulator Bets

One of the reasons behind the popularity of accumulator betting is that the odds are generally more attractive than simply placing a single bet on a football match. You might be convinced that Liverpool are going to win their next match, although odds of 1.33 mean that would have to risk a decent amount of cash in order to get a substantial return.

However, putting Liverpool in an accumulator with other teams means that we’re not betting at odds of 1.33 anymore. That is because their odds are MULTIPLIED with the odds of the other teams in our multiple bet and the price increases every time you add a new selection to your acca.

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Understanding Accumulator Odds

Let’s use a simple example. Manchester City, Wolves, Arsenal and Chelsea are all evens (EVS, 1/1) to win their respective matches. We place a £10 accumulator bet and this is how the odds are calculated:

£10 on Manchester City = £20 return
£20 return on Wolves = £40 return
£40 return on Arsenal = £80 return
£80 return on Chelsea = £160 return

You can see that the money rolls up each time and goes on to the next selection. In the above example, we would place £10 and potentially get a return of £160. £10 of that £160 would be our original stake, so the accumulator with 4 x evens selections effectively pays odds of 15/1. A nice big potential return for a modest stake in football betting.

As you can see, you don’t need to be a member of MENSA to work out your bet manually! The great news is that when you add different selections to your accumulator, the odds are automatically calculated by your online bookmaker. You can play around with the betting slip until you are happy with the selections and corresponding odds.

Here is an example of a simple five-fold starting with fractional odds:

Sheffield Wednesday 6/4
Arsenal 1/3
Luton Town 8/11
Colchester United 5/4
Liverpool 8/13

The simplest way, in my opinion, is to convert the odds into decimal format. For example, if you put a £1 single on Sheffield Wednesday at 6/4, you would get a return of £2.50. That effectively means that the decimal odds for Wednesday is 2.50 because this format takes into account the overall return from a £1 unit stake. Here are the decimal equivalents to the five-fold selections:

Sheffield Wednesday 2.50
Arsenal 1.33
Luton Town 1.73
Colchester United 2.25
Liverpool 1.61

Now we simply multiply all of the odds together to get the combined odds of our acca:

2.50 x 1.33 x 1.73 x 2.25 x 1.61 = odds of 20.84

Therefore a £10 bet would return £208.40.

So now you have two different ways of calculating the odds. If the prices are fairly simple such as the even money examples, I work it out in my head. If the prices are more complicated, break them down into decimal odds and multiply them together using a calculator. As mentioned, a bookmaker betting slip will also do the hard work for you.

How Do Betting Accumulator Odds Work?

So you’ve visited your favourite online bookmaker and you’re looking at the latest coupon. How on earth have the bookies been able to calculate the odds for every team in every match. The truth is that there are loads of variables that go into the prices such as:

  • League Standings
  • Latest Form
  • Team News
  • Motivation
  • Home Form v Away Form

In addition, the prices will change according to how many customers are betting on each selection. You might have seen a few odds changes for yourself on a Saturday afternoon. The price itself doesn’t tell us too much – we know that an 8/1 shot isn’t very likely to win while a 1/5 shot should in theory be an absolute banker.

How to Get Value on Your Accumulator Bets

However, we can translate these odds into implied probability. For example, if Sheffield Wednesday are 6/4 to win, then this suggests that they have a 40% chance of winning their match. If you believe that they have a better chance than the 40% implies, then that is something called “value” which means you might add them to your acca.

After a while, you will learn what prices stand out and which prices are far too short. A lot of people tend to fill their coupon with the obvious choices and supposed ‘dead cert’ – Celtic to win at home, Bayern Munich, Chelsea, Man City etc. But when you examine the odds the risk involved in predicting four games for combined odds of 2.40 is really not worth the risk:

Celtic 1.10
Bayern Munich 1.17
Chelsea 1.50
Man City 1.20

This type of accumulator would give you combined odds of 2.32 – which is a terrible price on the outcome of four matches. If you do your research and spot the matches with good value then you will maximise your returns and chances of winning. More often than not, with the right preparation, you will be able to pick a single winner at bigger odds than the combined price of a supposed bank four-fold.

So, you now feel more confident no doubt about accumulator odds and how the bet works. You should now check my article on how to win an accumulator bet, it’s one of my most popular pages on my site and can really help you make better accumulator bets.


Betting Expert
I've made What Acca to try and help people starting out with accumulator betting. The possibilities of these types of bets are pretty much endless, with the major attraction coming from the fact that a lot of money can be won for very little outlay. What Acca will hopefully teach you how to make more profitable accumulator bets whilst also eradicating some of the mistakes that I have made over the years.

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