Bookmaker Margin Explained: The Number That Decides If You Win

Add up the implied probability of every outcome in a market. Take a coin flip priced at 1.90 and 1.90: that is 52.6% plus 52.6%, which comes to 105.2%. The extra 5.2% is the bookmaker's margin, and it is the only reason a bookmaker is a business rather than a charity.

Margin is not evenly spread. On a Premier League match result you might face 4%. On a correct-score market you can face 15%. On an in-play accumulator, more still. Every percentage point of margin is a percentage point you must out-predict before you break even, which is why the market you choose matters more than the team you pick.

This is also why comparing bookmakers is not a nicety. The same selection at 1.90 versus 2.00 is a 5% difference in return on a bet you were going to place anyway. Over a season that gap is larger than most people's entire edge.

Key points

Margin = sum of implied probabilities minus 100%
Match result markets typically carry 3-6%; correct score and specials carry 10-15%
Lower-margin markets need a smaller edge to beat
Comparing three books routinely finds 5-8% better on the same selection

Frequently asked

What is a normal bookmaker margin?

On major football match-result markets, roughly 3-6% at the sharper books and 6-9% at recreational ones. Niche markets, specials and accumulators carry much more. Anything above 10% should make you ask whether the market is worth playing at all.

Does a lower margin mean better odds?

Yes, directly. Margin is the amount the bookmaker has taken out of the true probabilities. A 3% market gives you more of the real price than an 8% one on the identical event.

How do I remove the margin to see the true probability?

Divide each outcome's implied probability by the total. If the book adds to 105%, divide each by 1.05. That gives you the bookmaker's honest opinion, which is a far better starting point than your own guess.

Put it to use

Bookmaker Margin Explained: The Number That Decides If You Win

Key points

Frequently asked

Put it to use

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