How are football margins calculated?

Being a consistently profitable bettor is very challenging. Even if you are smart enough to regularly predict sports outcomes correctly, the bookmakers tip the odds in their favour to ensure they don’t lose out too often. 

They do this by employing margins. It is essential to know what these are and how they are calculated before placing a bet. They affect the value in every selection you make. 

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It is important not to confuse this essential aspect of odds pricing with the winning margin market upon which you can bet for football matches. Let’s investigate both types of margin.

Margins on bets

Every single market in betting comes down to probability. What is the likelihood of each outcome occurring?

In the football match odds market there are three options: home win, away win or draw. If we look at the 9,880 Premier League matches which took place between the start of the 1999/00 season and the end of 2024/25, we find 45.9% were won by the home team. 

The visitors collected three points in 29.4% of the games, with the remaining 24.7% ending all square. 

Away teams have done a little better in recent years but the percentages don’t shift too far from those averages each season. However, these are not the probabilities that a given game will end with each outcome. The standard of the team varies far too wildly for that.

Read: How to bet on corners, strategy, tips and statistics 

In March 2025, league leaders Liverpool hosted bottom side Southampton at Anfield. The Saints took a surprise lead before the Reds recovered to win. 

Even when 1-0 up, the chances of a shock away win may still have been below 29.4%, such was the disparity in form between the two teams. 

We can calculate a bookmaker’s assessment of the probabilities that Liverpool would win, draw or lose at the start of play using the pre-match odds in decimal format. 

We simply divide 100 by the price to get our percentages. Here are the findings using prices from Ladbrokes.

You will notice a problem. The three percentages add up to 104.9%, which is impossible. 

Except that in betting it is not. The difference between the total and 100 is 4.9%, which is the bookmaker’s profit. These figures will not be the same with every firm, or in every market, so it pays to shop around before placing your bet.

Websites such as OddsPortal enable you to sort bookmakers to find who gives the highest percentage pay out for a given match. 

For instance, Coral had the same prices for a Liverpool and Southampton win in the above example but priced the draw at 11.00 rather than 10.00.

This means the tie represented 9.1%, making the combined total 104%. Their profit margin was lower than Ladbrokes in this case, so bettors looking to place a match odds wager would be smart to pick Coral in this instance.

Calculating probabilities using the margin

Once we know the bookmaker’s profit margin, we can calculate what they believe to be the probability of the given outcome. Bettors often use matched betting to decipher where the best value lies across the industry. 

The formula we need is a touch more complicated than when working out the margin but is consistent for all outcomes. 

We subtract the total percentage from 200, then divide that new figure by our decimal price. Dividing this by 100 then gives us our probability. 

Let’s return to Liverpool against Southampton from March 2025, using Ladbrokes’ odds.

Once again, our percentages don’t add up exactly to 100. However, this is due to rounding errors from our multitude of equations rather than anything on the part of the bookmaker. 

We don’t need these figures to be exact; they simply give us an indication of the true probability as estimated by the bookie. By comparing these to our own predictions, we can determine where the value lies. 

Using expected goal data from FBRef suggested a Liverpool victory was approximately 3% less likely than Ladbrokes thought, with the probability of a draw around 3% higher. 

In a match as one-sided as this appeared to be, it did not make sense to back the draw even though it looked like a value selection based on these findings. Nonetheless, searching for this type of margin is a sensible strategy before placing a bet.

To get any true value out of Liverpool beating the worst team in the division, it would make sense to look at the 'Winning Margin' market.

Winning margin market

A 'Winning Margin' bet is simply when you specify by how many goals your chosen team will win. 

It is like a handicap bet, except you must specify an exact figure. If your team wins by more than the selected number, your wager will be unsuccessful. 

Such was Liverpool’s likely dominance of the game with Southampton in our previous example, their odds were shorter to win by two or three goals than they were to win by one. 

With so many variables at play, it is very hard to be successful with a winning margin bet. For instance, if the favourite goes 3-0 up, they may ease off towards the end of the game. 

Read: What is in-play football betting and how to exploit the markets?

The manager may opt to take their players off early and replace them with lesser members of their squad. It would not then be a surprise if the underdog scored, lessening the margin of victory.

Data on wins and losses by different margins is available on websites such as SoccerStats.com. The team that had the most victories by exactly two goals in the 2024/25 Premier League was Liverpool, with 11. The team that suffered the most two-goal defeats, with 10, was Southampton.

The score when they met at Anfield? 3-1 to the Reds. Hopefully you had bet on Liverpool to win by 2 goals, which would’ve been priced at approximately 3/1. 

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Never bet more than you can afford to lose. Stop betting if you are angry, emotional or under the influence of alcohol.

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