Expected Value Calculator
Determine if a bet has positive or negative expected value. Enter your estimated probability and the odds offered to calculate EV, ROI, and projected profit.
How Expected Value Works
Expected value is the foundation of profitable sports betting. Every professional bettor focuses on finding +EV opportunities where the true probability of an outcome exceeds what the odds imply.
The EV Formula
EV = (Win Probability × Net Profit) - (Loss Probability × Stake). When expressed per unit staked: EV = p × (d - 1) - (1 - p), where p is your true probability and d is the decimal odds.
Interpreting EV
An EV of +5% means you expect to profit $5 for every $100 wagered over the long run. A negative EV means the house has the edge. The magnitude of the EV tells you how strong the opportunity is.
Batch Comparison
Use batch mode to compare multiple betting opportunities side by side. Focus your bankroll on the highest +EV bets available to maximize your long-term profit.
Frequently Asked Questions
What is expected value (EV) in sports betting?
Expected value (EV) is the average amount you can expect to win or lose per bet over the long run. It is calculated as: EV = (probability of winning × profit if win) - (probability of losing × stake). A positive EV (+EV) means the bet is profitable long-term; negative EV (-EV) means you lose money over time.
How do I estimate my true probability?
True probability estimation is the core skill in sports betting. Methods include: building statistical models, comparing odds across multiple sharp sportsbooks (the no-vig average of sharp books is a good proxy), analyzing historical data, or using the implied probability from a low-vig book like Pinnacle as a baseline.
What makes a bet +EV (positive expected value)?
A bet is +EV when your estimated true probability of the outcome is higher than the implied probability from the odds. For example, if you believe a team has a 55% chance of winning but the odds imply only 52.38% (-110), the bet is +EV. The EV is 55% × 0.909 - 45% × 1 = +5.0% per unit.
Can I still lose money on +EV bets?
Yes, absolutely. +EV means profitable in the long run, but variance (luck) dominates in the short term. Even a strong +5% EV bettor will have losing days, weeks, and months. This is why bankroll management (see our Kelly Criterion calculator) is essential - proper bet sizing ensures you survive the inevitable downswings.