Betting Margins Explained

Learning how to calculate betting margins is a crucial skill for every punter. Once you master this simple calculation, you can easily find the best odds in every market.

Written by Steven Hubbard
Verified by BettingLounge team
Last updated 27/02/2024

Bookmakers constantly claim to have the highest odds available, but with so many claiming to have the best odds, how do we know who’s telling the truth? Easy. On BettingLounge, you can compare betting odds across 10+ UK bookmakers. These odds are updated in real-time, so you know who has the best odds.

To start, bookies offer odds lower than the actual probability of an event occurring. This is known as the betting margin. Essentially, it is the added price a betting site “charges” you to place the bet, ensuring a profit regardless of the outcome.

As an example, imagine betting margins as a coin toss. In this example, both heads and tails represent a 50% chance each.

This is a 100% market that gives no advantage to the punter or bookie. But this is not the case. In reality, each betting site will add a margin to ensure they always have the advantage over punters.

Working out betting margins using the decimal odds format is the easiest way. If you struggle with decimal odds, check out our betting odds guide.

How to Calculate the Betting Margins

There is a simple equation we use to calculate the betting margins. You can use this calculation across all the sports and markets, as they tend to differ significantly.

It's important to remember the higher the margin, the lower the value for a punter. Margins are the best way to compare odds and find their actual value.

Also, live betting margins are much higher than in pre-match markets.

To calculate the margin for a two-way market, like basketball or tennis, use this example:

(1/decimal odds) *100 + (1/decimal odds) *100 = Betting margin

Unibet tennis: Casper Ruud 2.48 vs David Ferrer 1.54

(1/2.48) *100 +  (1/1.54) *100 = 40.3 + 64.9 = 105.2 = 5.2% margin

William Hill tennis: Casper Ruud 2.50 vs David Ferrer 1.50

(1/2.50) *100 + (1/1.50) *100 = 40 + 66.6 = 106.6 = 6.6% margin.

This simple calculation shows that Unibet offers a 1.4% better margin than William Hill for this tennis event.

This is important for value over the long run. Find the best odds with the lowest margin to increase your potential profit.

To calculate margins for a 1x2 market like football, use this example:

(1/home odds) *100 + (1/draw odds) *100 + (1/away odd) *100 = Betting margin

Unibet football: Wolfsburg 1.75 (home) X 3.70 (draw) Norwich City 3.95 (away)

(1/1.75) *100 + (1/3.70) *100 + (1/3.95) *100 = 57.1 + 27 + 25.3 = 109.4 = 9.4% Margin

William Hill football: Wolfsburg 1.70 (home) X 4.0 (draw) Norwich City 4.0 (away)

(1/1.70) *100 + (1/4.0) *100 + (1/4.0) *100 = 58.8 + 25 + 25 = 108.8 = 8.8% Margin

Now you can see William Hill is slightly better, with a 1.6% margin less than Unibet.

These are only meant as examples to show how much bookies actually “charge” you to place a bet.

Our football margins test showed a massive difference in margins between the best and worst.

Best betting margins in the UK

BetVictor consistently offers the best odds and lowest margins for betting on football in our tests.



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Betting Margins Conclusion

Now you know how to calculate betting margins for two way and three-way markets, you can now easily identify the best odds and lowest betting margins across bookmakers.

Although betting margins are ever-changing, you can still use them to get an idea of the best bookies to use if you want the most value for your money.

Check out the Betfair betting exchange if you are searching for a fairer market. They will charge a 2-5% commission on winnings only, whereas, bookmakers add their margins regardless of whether you win or lose.

Steven is an experienced iGaming content writer who has been working in the industry since 2018. He is passionate about sports betting and enjoys writing about all aspects of the industry, including bookmaker reviews, betting tips and strategies, and news and analysis. If you have any questions about online gambling in the UK, please don't hesitate to contact him.