Free calculator
Expected Value Calculator
Positive over the long run — but only if your probability is right.
How to use it
Change any input and the results update immediately. The values are also written into the address bar, so you can bookmark a calculation or paste the link to someone else and they will see exactly the same numbers.
Everything here computes with the same functions that produce the grades inside WeBall, so a number on this page will never contradict a number on a bet card.
What the term means
The average result of a bet per unit staked if it could be repeated indefinitely.
Expected value converts an edge into money. Multiply your win probability by the decimal odds and subtract one: a 55% chance at +110 gives 0.55 × 2.10 − 1 = +0.155, or about 15.5 cents of profit per dollar over the long run.
Full definition of expected value →
Learn the math behind it
A calculator is faster than doing this by hand, but knowing why the formula works is what lets you spot when a number is wrong. Read the full guide →