What expected value (EV) is
It's the average outcome you'd expect from a bet if repeated infinitely, given the offered odds and the real probability (as you estimate it) of the event happening.
Formula
EV = stake × (probability × odds − 1). A positive EV means the bet is mathematically favorable long-run — assuming your probability estimate is accurate.
Important notice
This is a purely educational, mathematical tool. EV depends entirely on the quality of your probability estimate — if it's wrong, the calculation has no practical value. This calculator is not an encouragement to bet, and betting carries a real risk of losing money.
Frequently asked questions
Does a positive EV guarantee I'll win this bet?
No. EV is a long-run average over many repetitions — a single bet can still lose even with positive EV.
Where does the "estimated probability" come from?
It's your own estimate (or from some model/analysis) of the real chance of the event — it's not provided by the sportsbook, which only sets the odds.
Does this tool recommend betting?
No. It's a math calculator for educational purposes; it does not encourage or recommend betting of any kind.