What is a surebet?
When prices at different books cover every outcome for less than the total stake, with the formula and worked examples.
A surebet (an arb) is a set of bets on every outcome of one market, each at the book that prices it best, where the prices are generous enough that the return beats the total stake whichever outcome wins.
The test
Take the best decimal price for each outcome, at any book, and add up 1 / odds:
- Above 1: no surebet. The books' margins win.
- Below 1: a surebet. The gap is your margin.
Margin = 1 − (1/odds₁ + 1/odds₂ + …)
A two-way example
Stake 1,000 in total, split so both outcomes return the same:
| Leg | Odds | Stake | Returns if it wins |
|---|---|---|---|
| Player 1 at Book A | 2.10 | 493.98 | 1,037.36 |
| Player 2 at Book B | 2.05 | 506.02 | 1,037.34 |
Whoever wins, about 1,037 comes back on 1,000 staked. How the split is worked out: Stake splitting.
Three-way
Football's home / draw / away needs three legs, often at three books. Same test: the three 1/odds must add up to less than 1. Three legs means three chances for a price to move before you've placed them all.
Why they exist at all
Books set prices independently, move them at different speeds and sometimes make mistakes. For a short while one book is generous on one side while another is generous on the other. Our logs show the life of a confirmed surebet is usually measured in seconds to minutes, not hours: the daily verification log publishes the median every day.
Try your own numbers in the free surebet calculator.
See it on real data
A free account shows up to 3 live surebets, each 0.99% or less, every leg re-checked at its book. No card needed.