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Expected Value Calculator

Find out if a bet is +EV before you place it. Plug in odds and your win probability — get the dollar EV, ROI, and breakeven win rate.

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Formula

EV = (p × profit) − (q × stake)

EV = (0.45 × $150) − (0.55 × $100)

Expected Value Per Bet
+$12.50
+12.5% ROI+EV
Breakeven Win Rate
40.0%
You need 40.0% to break even
Your Edge
+12.5%
vs implied probability
EV per $100
+$12.50
standardized EV
After 1,000 Bets
+$12,500
expected profit

Win Rate vs Breakeven

0%Breakeven: 40.0% | Your prob: 45%100%
Learn what expected value means and why it matters →

About the Expected Value Calculator

Expected value (EV) is the average amount you expect to win or lose per bet if you placed the same wager an infinite number of times. A positive EV (+EV) bet wins money long-term; a negative EV (-EV) bet loses money long-term. EV is the single most important number in profitable betting.

Use this calculator to evaluate any wager. Enter the American odds, your stake, and your true win probability. The output shows the EV per bet, your edge versus the implied probability, the breakeven win rate the odds require, and the projected profit over 1,000 identical bets.

Formula

EV per betEV = (p × profit) − (q × stake)
Wherep = your win probability, q = 1 − p

Frequently asked questions

What is a +EV bet?
A +EV (positive expected value) bet is one where your true win probability beats the probability implied by the odds. For example, a coin flip at +110 odds is +EV: you win $110 half the time and lose $100 half the time, netting +$5 per bet on average.
How do I know my win probability?
You don't — that's the hard part of betting. Pros estimate true win probability using models, sharp consensus lines, no-vig fair odds from market-leading books like Pinnacle, or by removing the vig from the average market line.
What's the difference between EV and edge?
EV is a dollar amount per bet. Edge is the percentage gap between your estimated win probability and the implied probability from the odds. A 5% edge means you win 5% more often than the odds suggest you should.
How much EV per bet do I need to be profitable?
After vig, you typically need a real edge of 2–3% or more to overcome variance and book limits. Most pros target +EV bets of at least +1% to +3% ROI per wager.
Why does the calculator show ROI as well as EV?
EV depends on stake size, ROI is normalized. A $5 EV on a $100 bet (5% ROI) is the same edge as a $50 EV on a $1,000 bet. ROI lets you compare bets of different sizes head-to-head.

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