Expected Value (EV) Calculator
See if a bet is +EV before you place it.
How it works
Expected value is the average profit (or loss) of a bet if you could repeat it forever: EV = p · odds − 1, times your stake. A positive EV means the bet wins money on average; a negative EV means it bleeds.
The break-even probability is 1 ÷ odds — the win rate you need just to not lose. Your edge is how far your own probability sits above that. If you have no honest edge, no staking system can rescue a −EV price.
Expected Value (EV) Calculator
Expected value (EV) is the single number that decides whether a bet is worth making. This free EV calculator takes the odds, your estimated win probability and your stake, and tells you the average profit or loss per bet, your edge over the bookmaker, and the break-even probability you actually need.
What expected value means
EV is what a bet would earn on average if you could repeat it under identical conditions forever. The formula is EV = stake × (p × odds − 1), where p is your win probability and odds are decimal. A positive result is a +EV bet that makes money over time; a negative result is a −EV bet that loses.
One bet is mostly luck. EV is about the long run: place hundreds of +EV bets and the math grinds in your favour, even though any single one can lose.
Edge and break-even probability
Every price has a break-even probability of 1 ÷ odds — the win rate that makes the bet exactly neutral. At 2.00 you need to win 50% of the time; at 1.50 you need 66.7%. Your edge is how far your own honest probability sits above that break-even line.
If your estimate only matches the break-even probability, your EV is zero before any bookmaker margin — and negative after it. Real value requires a genuine, repeatable edge.
How to use the EV calculator
Enter the decimal odds you can actually bet at, your honest win probability, and your stake. The calculator returns the expected value in your currency, the EV as a percentage of your stake, your edge in percentage points, and the fair odds that your probability implies.
How do I calculate the expected value of a bet?expand_more
EV = stake × (win probability × decimal odds − 1). If the result is positive the bet is +EV; if negative it loses money on average.
What is a good EV percentage?expand_more
Any positive EV beats a coin flip with the bookmaker. Sharp sports bettors often work with edges of 1–5%; the bigger and more reliable the edge, the better, but honest estimation matters more than chasing a big number.
What is break-even probability?expand_more
It is 1 ÷ decimal odds — the win rate at which a bet neither wins nor loses. You need to beat it (after margin) for the bet to be +EV.
Does +EV guarantee I win?expand_more
No. +EV means you profit on average over many bets, not on any single one. Variance can produce long losing runs even with a real edge — which is why bankroll management matters.