Expected Value (EV) Calculator

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Find out whether a bet has value — and how much. Enter your own estimate of the win probability, the decimal odds on offer and your stake. It returns the expected value in money and as a percentage edge, your fair odds, and whether the price is +EV, break-even or −EV.

How expected value is worked out

For a win probability p, decimal odds d and stake S:

EV = S × (p × d − 1), and your fair odds are 1 ÷ p.

Example: you rate a team at 55% (p = 0.55, fair odds 1.82) and the book offers 2.00. EV on $100 = 100 × (0.55 × 2.00 − 1) = +$10, a 10% edge. If the same team were only 1.70, EV = 100 × (0.55 × 1.70 − 1) = −$6.50 — no value, even on a team you fancy. The price, not the pick, decides value.

The honest catch

EV is a long-run average over many identical bets — any single bet still wins or loses in full. And it's only positive if your probability is genuinely more accurate than the market, which is the hard part. Read the full picture in our value betting guide, then use the Kelly Calculator to turn a real edge into a stake size.

Calculations are exact from the numbers you enter. This tool is for information only and assumes a single bet paying out at the stated decimal odds.

Related guides & tools

• Value betting explained — expected value, fair odds and closing line value.
• The bookmaker margin (vig) — why the offered price is usually shorter than fair.
• Kelly Criterion Calculator — size a +EV bet by your bankroll and edge.
• Margin & Fair Odds Calculator — a fair-odds baseline for your probability.