How is expected value calculated?

With decimal odds, EV = win probability x odds - 1. A bet at 2.20 that wins 50% of the time has EV of 0.5 x 2.20 - 1 = +10%, an average of 10 per 100 staked over many bets like it.

Where does the win probability come from?

Choose one of three sources. Sharp market takes every outcome of a sharp bookmaker’s market and removes the margin with the logarithmic method OddsHub uses. Fair odds takes a margin-free price you already have. Probability takes your own estimate as a percentage.

What do the break-even odds mean?

They are the lowest price at which the bet stops losing money on average, 1 divided by the win probability. At 50% that is 2.00. Any price above it is positive EV for that probability.

Does positive EV mean the bet will win?

No. EV is an average over many similar bets. A single +EV bet still loses often, and if the probability you enter is wrong, the EV is wrong with it. Treat the result as arithmetic on your inputs, not a forecast.

Expected value (EV) calculator

Check whether a price is worth taking. Enter your odds and the true win probability, from a sharp market, a fair price or your own estimate, to see the expected value of the bet. Free, no account, decimal, American and fractional odds.

Expected value

Your odds

Stake

True win probability from

Sharp odds, your side

Sharp odds, other side

Fair probability after removing the margin: 47.48%

Expected value: +4.45%
Per bet, on average: +4.45
Break-even odds: 2.11

At 47.48% the price is above fair: over many bets like this one the average result is +4.45 per 100.00 staked. Any single bet still wins 120.00 or loses the stake.

How it works

Expected value is what a bet returns on average if you could place it many times. For decimal odds and a win probability p:

EV % = p x odds - 1

Multiply by the stake for the average result in money. The bet wins stake x (odds - 1) with probability p and loses the stake otherwise, so the two outcomes are weighed by how likely they are. When p is exactly 1 / odds, EV is zero; that price is the break-even line.

The hard part is p. With Sharp market the calculator takes every outcome of a sharp bookmaker’s market, removes the margin with the logarithmic method and reads the fair probability of your side, the same way OddsHub prices every value bet. A price of 2.20 against a sharp 2.05 / 1.86 market is about +4.5% EV. For the fair price on its own, use the no-vig calculator.

From one bet to every market

Doing this by hand works for a bet you are already looking at. The free value bets page runs the same comparison across every bookmaker and lists the prices above the fair line. Size a +EV bet with the Kelly criterion calculator, and after the match check whether you beat the close with the CLV calculator or the Pinnacle closing odds lookup. Closing line value is how you find out, over a few hundred bets, whether the edge was real.

More betting calculators

Calculators show arithmetic, not predictions. No result here guarantees a profit, and betting always carries the risk of losing your stake. Bet only what you can afford to lose; help and limits are on the responsible gambling page.

Frequently asked questions

How is expected value calculated?: With decimal odds, EV = win probability x odds - 1. A bet at 2.20 that wins 50% of the time has EV of 0.5 x 2.20 - 1 = +10%, an average of 10 per 100 staked over many bets like it.
Where does the win probability come from?: Choose one of three sources. Sharp market takes every outcome of a sharp bookmaker’s market and removes the margin with the logarithmic method OddsHub uses. Fair odds takes a margin-free price you already have. Probability takes your own estimate as a percentage.
What do the break-even odds mean?: They are the lowest price at which the bet stops losing money on average, 1 divided by the win probability. At 50% that is 2.00. Any price above it is positive EV for that probability.
Does positive EV mean the bet will win?: No. EV is an average over many similar bets. A single +EV bet still loses often, and if the probability you enter is wrong, the EV is wrong with it. Treat the result as arithmetic on your inputs, not a forecast.