Free tool
Surebet calculator
Two or three outcomes, decimal odds, one total stake. Get the margin, each stake and what every outcome pays. No account, nothing saved.
Surebet: margin 1.42%
Outcome 1
487.68
at 2.08, pays 1,014.38
Outcome 2
512.32
at 1.98, pays 1,014.38
- Smallest payout
- 1,014.38
- Smallest payout minus amount staked
- 14.38
Assumes every leg is accepted at these odds and settles under the same rules. Odds move, books cap stakes and close markets: check each leg before you place it.
The maths is the easy part
Finding a surebet that is still there when you place it is the hard part. Arbistoteles scans 10 books, re-reads every leg at its book before a surebet reaches the board, and takes it off when a leg goes stale.
Questions
- What is a surebet?
- A set of bets on every outcome of one event, at different books, whose odds add up to a margin above zero: 1/odds summed over all outcomes is below 1. Split the stake right and every outcome pays about the same.
- How is the margin worked out?
- Margin = 1 - (1/odds1 + 1/odds2 [+ 1/odds3]). Each stake = total x (1/odds) / that sum, so each outcome pays total / sum. Rounded stakes pay a little differently per outcome; the calculator shows each payout.
- Why did the surebet I found disappear?
- Odds move, markets close and books cap stakes, often within seconds. A margin is only real if every leg is still there at that price when you place it. Arbistoteles re-reads every leg at its book before it shows a surebet.
- Do both bets have to settle the same way?
- Yes. Check that every leg covers the same outcome under the same rules: overtime included or not, void on retirement, dead heat, push on whole lines. A rule mismatch can leave one leg losing while the other is void.