Expected value calculator
Compare a price with a fair price or your own probability to see the expected value per stake and the edge in percent.
Read as decimal odds: 2.10
Read as decimal odds: 2.00
Expected value +5.00 on a stake of 100.00 (+5.0% edge).
An average over many bets like this one, never a forecast of one result. It is only as good as the estimate.
How it works
Expected value is what a stake is worth on average over many repeats: the chance of winning times what a win pays, minus the chance of losing times the stake.
For decimal odds it comes down to probability × price − 1 per unit staked. Above 0, the price pays more than the chance it stands for; below 0, less. That figure as a percentage is the edge.
The probability is the hard part. A fair price from the no-vig calculator is one estimate; your own is another. The result is only as good as that number.
Worked example
A price of 2.10 (+110) on an outcome whose fair price is 2.00, a 50% chance, with a stake of 100.
- Expected value per unit staked = probability × price − 1 = 0.5 × 2.10 − 1 = 0.05, an edge of +5.0%.
- A win pays 110.00 in profit and a loss costs 100.00: 0.5 × 110.00 − 0.5 × 100.00 = +5.00.
- So the stake of 100 is worth +5.00 on average. Any single result is still a win or a loss.
- At 2.00 the edge is 0, and at −110 (1.91) it is −4.5%.