Betting calculator
Arbitrage Calculator
Use this arbitrage calculator to check whether a set of odds creates an underround and calculate how to split your stake across all outcomes.
Enter your stake and odds
Add every possible outcome in the market, then enter the odds available for each one.
| Outcome | Decimal odds | Implied probability | Stake | |
|---|---|---|---|---|
| 47.62% | £50.00 | |||
| 47.62% | £50.00 |
This example creates an underround. Splitting £100.00 across all outcomes would return about £105.00, giving an estimated profit of £5.00.
What is arbitrage betting?
Arbitrage betting is when the available odds allow every possible outcome in a market to be covered for a profit. This usually happens when prices across different bookmakers or exchanges create an underround.
The maths can look simple, but real-world execution is harder. Odds can move, bets can be limited, markets can suspend and exchange commission can reduce or remove the profit.
Arbitrage formula
Implied probability = 1 ÷ decimal odds × 100
Book percentage = all implied probabilities added together
Arbitrage exists in theory when book percentage is below 100%
Arbitrage example
If Outcome A is available at 2.10 and Outcome B is also available at 2.10, each outcome has an implied probability of 47.62%.
| Outcome | Decimal odds | Implied probability |
|---|---|---|
| Outcome A | 2.10 | 47.62% |
| Outcome B | 2.10 | 47.62% |
47.62% + 47.62% = 95.24%
Because the total is below 100%, this is an underround. In theory, that allows both outcomes to be covered for a profit.
Why arbitrage can be difficult in practice
- Odds can move before all bets are placed.
- Stake limits can prevent the correct stake split.
- Markets can suspend before the second bet is placed.
- Bookmakers may have different settlement rules.
- Exchange commission can reduce the profit.
- Account restrictions can affect repeat use.