Free tool

Expected value (EV) calculator

Enter the odds, your own estimate of the win probability, and your stake. The calculator returns the expected value in dollars and as a percent of stake, plus your edge over the line's break-even number.

Expected value

Odds

American, e.g. +150, -110

Your win probability

your true estimate, %

Stake

$ per bet

Expected value

+12.5% of stake per bet

+$12.50

Your edge

Your 45% vs the line's 40.0%

+5.0 pts

Break-even probability

What you need to win just to break even

40.0%

A bet is +EV when your win probability beats the odds’ break-even number. Over the long run, only +EV bets make money.

What expected value tells you

Expected value is the average profit or loss a bet would return if you could place it many times. It weighs the amount you win by your chance of winning against the amount you lose by your chance of losing. A positive number means the bet makes money over the long run at that price; a negative one means it bleeds.

Why your probability is the input that matters

The odds set the payout, but whether a bet is +EV depends on your win probability versus the break-even number baked into the price. A -110 line needs 52.4% to break even. If your honest estimate is higher than the line's implied probability, the bet is +EV, and that gap is your edge.

Frequently asked

Q.01

What is a +EV bet?

A positive expected value (+EV) bet is one where your true win probability is higher than the probability implied by the odds. Over many bets, +EV wagers profit and -EV wagers lose, regardless of any single result. Finding +EV consistently is the foundation of every winning bettor's approach.

Q.02

How is expected value calculated?

Multiply your win probability by the profit you'd win, then subtract your loss probability times your stake. At +150 with a 45% win estimate on a $100 bet: 0.45 × $150 minus 0.55 × $100 = a +$12.50 expected value, or +12.5% of stake per bet.

More tools