Calculators

What it does

Expected value (EV) is what a bet would return on average if you could repeat it many times at the chance you believe is true. It compares your probability with the odds on offer.

A positive EV means the odds are longer than your chance suggests; a negative EV means they are shorter. Any single bet still either wins or loses.

How to use it

1. Enter the odds on offer.
2. Enter your probability that the bet wins, as a percentage.
3. Enter your stake.
4. Read the expected profit, the edge, and the fair odds at your probability.

Worked example

Made-up numbers, for learning

Odds of 2.50 are on offer. You think the chance of winning is 45%, and you stake £10.

The odds imply a 40.0% chance, lower than your 45%. Fair odds at 45% would be 2.22.

The edge is 45% × 2.50 − 1 = 12.50%, so the expected profit is +£1.25 on £10.

Things to watch

• The answer is only as good as your probability. If 45% is too high, the edge may not be there at all.
• EV is an average over many bets. This one bet either wins or loses the whole stake.
• The edge is for the price you entered. If the odds change, work it out again.

Key words

Expected value (EV)

The average profit or loss per bet over many repeats, at your probability.

Edge

Expected profit per £1 staked: probability × odds − 1.

Fair odds

The odds that match your probability exactly: 1 ÷ probability.

Implied probability

The chance the price suggests: 1 ÷ decimal odds.