Value and Kelly calculator

Enter a price and the probability you think is right. The calculator returns the edge, the expected value of the bet, and the full Kelly stake.

36.4%
Implied probability
What the price says
+5.6%
Your edge
Percentage points
15.50
Expected value
15.50 per 100 staked
8.9%
Full Kelly stake
Of bankroll
Your probability is higher than the price implies, so this bet has a positive expected value at the number you entered.

Edge is your probability minus the probability the price implies, in percentage points. A price of 2.75 implies 36.4%; if you think the real chance is 42%, the edge is 5.6 points.

Expected value turns that edge into money: the average profit per bet if your probability is correct and you made the same bet many times. A single result tells you nothing about whether the number was right.

Kelly is the stake that maximises long-run growth of a bankroll. It assumes your probability is accurate, and it is unforgiving when it is not: most people who use it stake a fraction of it, commonly a quarter or a half. When the price already implies more than your probability, Kelly is zero, which means no bet rather than a bet the other way.

All three depend entirely on your probability being honest. That is the hard part, and it is what our model is for.

See the same maths on real matches

Every pick we publish carries the model's probability, the odds we took and the settled result, losers included.

These calculators are for information only and are not betting advice. Nothing here predicts an outcome or promises a return. 18+, and only where sports betting is legal where you live. See our disclaimer.