UK · Sports betting · Free tool
Bookmaker margin calculator: how much does the bookie keep?
Enter a bookmaker’s odds on every outcome of a market, in fractional or decimal format, to see how much it keeps, the fair odds with its margin removed, and, with a second bookmaker’s odds, which pays more on each outcome.
Sportsbook margin calculator
Sportsbook A keeps
Payout 95.5%4.55%
Sportsbook A keeps about £4.55 of every £100 bet on this market, on average
- Overround (A)
- 4.76%
- Payout rate (A)
- 95.45%
- Book B keeps
- 5.26%
- Payout rate (B)
- 94.74%
- Fair odds, margin removed (A)
- 1/1 / 1/1
Sportsbook A keeps 0.72% less of every bet
Outcome by outcome
| Outcome | A | B | Better | Extra |
|---|---|---|---|---|
| 1 | 10/11 | 4/5 | Book A | +£10.91 |
| 2 | 10/11 | 1/1 | Book B | +£9.09 |
| 3 | — | — | — | — |
Margin assumes bets follow the fair probabilities (proportional method). Outcomes are in the order you entered them. “Extra” is how much more the better price returns on your stake if that outcome wins.
How the calculator works
A bookmaker never offers fair odds. Add up the implied probabilities of every outcome in a market and you get more than 100%: the excess is the overround, and it’s how the bookie makes money whoever wins. At 10/11 on both sides of a two-way market, each side implies 52.4%, together 104.8%, and the bookmaker keeps about 4.5% of everything staked on that market over time.
Enter the odds a bookmaker offers on each outcome, in fractional, decimal or American format, and the calculator shows how much it keeps, the share it pays back, and the fair odds with the margin removed. Add a second bookmaker’s odds on the same match to see which keeps less, and which pays more on each outcome. Comparing prices like this is the simplest way to cut what betting costs you, and betting exchanges, which charge commission on winnings instead, can be compared with our exchange commission calculator.
Typical margins
What a bookmaker keeps at common UK prices, computed with the same formula as the calculator.
| Market and prices | Overround | Bookie keeps | Pays back |
|---|---|---|---|
| Two-way market at 10/11 and 10/11 | 4.76% | 4.55% | 95.45% |
| Two-way market at 5/6 and 5/6 | 9.09% | 8.33% | 91.67% |
| Two-way market at 4/5 and evens | 5.56% | 5.26% | 94.74% |
| Football 1X2 at 11/10, 23/10 and 11/4 | 4.59% | 4.39% | 95.61% |
| Football 1X2 at 5/4, 12/5 and 2/1 | 7.19% | 6.71% | 93.29% |
Frequently asked questions
What is the overround?
The amount by which a bookmaker’s implied probabilities add up to more than 100%. At 10/11 on both sides of a two-way market, each side implies 52.4%, together 104.8%, and the bookmaker keeps about 4.5% of everything staked on that market over time.
How is what the bookie keeps calculated?
Hold = 1 − 1 ÷ (sum of the implied probabilities), which is what the bookmaker keeps if bets follow the fair probabilities. The payout rate is the rest. The calculator removes the margin proportionally to get the fair odds.
How do betting exchanges compare?
Exchanges don’t build a margin into the odds: you bet against other users, and the exchange takes a commission on your net winnings. Use our exchange commission calculator to compare an exchange price with a bookmaker’s.
Does a lower margin mean I will win?
No. It means you lose less on average. Even at a low margin, a bettor who picks at random loses part of everything staked over time.