Today’s margins
Margin: average across the races each bookmaker priced in full, from its last price before the off. Best price: share of runners on which it matched or beat every other bookmaker. Exchanges are left out (they charge commission instead of a margin).
The running record
Average margin by day, lowest shaded greenWhat is a bookmaker’s margin?
Every price implies a chance: 4/1 is 20%, evens is 50%. Add those up for every runner in a race and a fair book comes to 100%. A bookmaker’s book comes to more, and the difference is its margin (the overround). On a 20% margin the prices add up to 120%, which is the edge the bookmaker keeps over many races.
Is the lowest margin always the best place to bet?
Not always. Margins are averages: a bookmaker with a higher average can still have the best price on the horse you want. Many bookmakers also limit stakes for customers who win. Compare the price on your runner, then the terms.
Where do the prices come from?
The Racing API, which reports 20+ UK and Irish bookmakers. We check every few minutes from 7am to 10pm and keep the last price before each race for the record.
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