Overround and Takeout: What Is the Difference?

Overround and takeout are two ways of measuring the same thing: how much a bookmaker's prices are set to keep. Across the 28 races at the Ebor Festival in August, overround came to 28.1% and takeout to 21.9%. Both figures are right, and the gap between them is not a rounding difference.

Overround measures how far past a fair book the prices sit. Takeout measures the share of every pound staked that does not come back to punters. One is a way of comparing markets, the other is a cost in your money, and quoting one while meaning the other is how the same race ends up described two different ways.

Almost nobody searches for either word. People ask how much the bookies keep, or why the odds seem stacked, and that is the language we use everywhere else on this site. If you have met "overround" on a betting forum and never been quite sure what it meant, this is the page.

Two ways to measure the same book

Start with the book itself. Turn every runner's price into a percentage and add them up. In a fair race the total would come to exactly one whole. On the Ebor card it came to rather more.

Overround is how far above a fair book that sits. Take the book, subtract one, express as a percentage. A book of 1.281 gives 28.1%. It answers: how much more than a fair market is being charged here.

Takeout is the share of all money staked the book expects to keep. Take the book, subtract one, then divide by the book. The same 1.281 gives 21.9%. It answers: of every pound bet into this race, how much does not come back to punters.

Overround is always the larger of the two, and the gap widens as the book gets fatter. At St Leger Festival, the cheapest meeting we measured, overround was 21.4% and takeout 17.6%, a gap of 3.8 points. At Galway, the dearest, overround was 30.5% against a takeout of 23.4%, a gap of 7.1 points.

Which one you want

If you are asking what this costs me, use takeout. It is denominated in your money: a takeout of 21.9% means that share of every pound staked into the race does not come back to bettors as a group.

If you are comparing markets, use overround. It is the conventional measure, it is what you will see quoted elsewhere, and it scales more intuitively when you are ranking races or meetings against each other.

The one thing not to do is average them, or quote one and call it the other. We keep them in separate columns everywhere on this site and we do not publish a single figure called "margin", precisely because that word gets used for both and the two numbers then appear to contradict each other.

There is one more distinction worth having. Neither number is the bookmaker's profit. It is what the book is set to keep if money lands across the runners in the proportions the prices imply. It rarely lands exactly like that, and a bookmaker can lose heavily on a single race.

What all of this means for the Grand National, which is the one bet a great many people have all year, has a page of its own.

A word on all of this

None of these pages is a tip, and none describes a way to win. They describe what betting costs, which is a different and more reliable subject. If your betting has stopped being fun, BeGambleAware has free, confidential help, and the National Gambling Helpline is on 0808 8020 133.

Common questions

What is the over-round in betting?

How far a book exceeds a fair market. Add every runner's implied chance together, take away the whole, and what is left is the overround. On the Ebor Festival card it averaged 28.1%.

What is takeout?

The share of everything staked into a race that the book expects to keep. It is always a smaller number than the overround on the same book, 21.9% where the overround was 28.1%.

Which is the bookmaker's profit margin?

Neither, exactly. Both describe how the book is set, not what the firm ends up with after the race is run.

Why does this site publish both?

Because they answer different questions and because quoting one as though it were the other is how two true figures end up contradicting each other. We never merge them into a single number.

What is a normal overround?

On the 269 festival races we measured it ranged from under a tenth in the smallest fields to nearly half in the largest. There is no single normal figure, which is rather the point.