Odds Format
Stake ($)
Odds
Win Probability (%)
Results
Enter stake, odds and win probability to see results.
What this calculator does
Expected value (EV) answers one question: if you could place this exact bet a thousand times, would you end up ahead or behind on average? A positive number means the price is better than you think it should be. A negative number means you’re paying too much for the outcome.
Enter the odds, your stake and your own estimate of the probability. The tool shows the expected profit or loss per bet, your edge in percentage points, and the probability the bookmaker’s price implies.
EV doesn’t tell you what will happen in a single match. It tells you whether a price is fair compared with your view of the game.
Step by step
1
Odds format
Decimal or fractional.
2
Stake
The amount you’re considering.
3
The odds
The price on offer.
4
Your probability
Your honest estimate, from 0 to 100%.
5
Results
EV, edge, implied probability, profit if it wins and loss if it doesn’t.
The maths behind it
Implied Probability = 1 / Decimal Odds
Edge = Your Probability – Implied Probability
EV = p x Stake x (Odds – 1) – (1 – p) x Stake
p is your probability as a decimal. The first part is what you expect to win, and the second part is what you expect to lose.
The answer is only as good as your probability. You can build that estimate from form, head-to-head records, team news, or a model such as our Poisson score predictor.
Worked examples
1
A draw that looks underpriced
BeginnerThe draw is 3.60, which implies 27.8%. Two defensive sides are meeting and you rate a draw at 31%. On a $50 stake: EV = 0.31 x $130 – 0.69 x $50 = +$5.80.
Positive EV: an edge of about 3.2 percentage points
2
The favourite trap
IntermediateA big favourite is 1.40, which implies 71.4%. Key players are missing and you rate them at 68%. On $100: EV = 0.68 x $40 – 0.32 x $100 = -$4.80.
Negative EV: they’ll probably win, but the price doesn’t pay enough for the risk
3
Why the price matters
AdvancedYou rate an away win at 44%. One site offers 2.30 and another offers 2.45. On $100: EV at 2.30 = +$1.20, EV at 2.45 = +$7.80.
Same opinion, same match: the better price makes the EV six times bigger
Questions people ask
QWhere does the 'true' probability come from?
Nobody knows it exactly. You estimate it from statistics, form, team news or a model. The more realistic your estimate, the more meaningful the EV. If you’re unsure, err on the cautious side.
QMy bet was +EV and it lost. Was the tool wrong?
No. EV is an average over many bets. A single positive-EV bet can lose, and often will. The number only shows up over a large sample.
QWhat's a realistic edge?
Bookmaker prices on major football leagues are sharp, so genuine edges are usually small, often a couple of percentage points at most. Big edges on popular matches usually mean the estimate is off.
QHow much should I stake on a +EV bet?
EV says whether a bet is worth considering, not how much to put on it. For sizing, try the Kelly stake calculator, ideally with a fraction, and only from money you can afford to lose.
