If you’ve spent any time in the sports betting world, you’ve probably heard the term “+EV” thrown around. But what does it actually mean, and why do serious bettors obsess over it?
In this guide, we’ll break down expected value from the ground up — no math degree required.
What Does EV Mean?
EV stands for Expected Value. It’s the average amount you can expect to win (or lose) per bet if you placed the same bet thousands of times.
+EV (Positive Expected Value): The bet is expected to be profitable over time.
-EV (Negative Expected Value): The bet is expected to lose money over time.
Think of it this way: a slot machine is a -EV game. For every $1 you put in, you can expect to get back about $0.93 in the long run. The casino keeps the rest. That’s their edge.
+EV betting flips that dynamic. Instead of the house having the edge, you have the edge.
How to Calculate Expected Value
The formula is straightforward:
EV = (Win Probability × Profit if Win) − (Loss Probability × Amount Lost if Lose)
Example
Let’s say you find a bet at +150 odds and you believe the true win probability is 45%:
Profit if win: $150 (on a $100 bet)
Loss if lose: $100
Win probability: 45% (0.45)
Loss probability: 55% (0.55)
EV = (0.45 × $150) − (0.55 × $100) = $67.50 − $55.00 = +$12.50
This means on average, every time you place this $100 bet, you expect to profit $12.50. That’s a strong +EV bet.
Try the expected-value-calculator→
Why the Sportsbook’s Line Isn’t Always Right
Sportsbooks set lines to balance their action and guarantee profit through the vig (juice). But they’re not perfect:
Public money moves lines away from fair value
Injuries and news take time to price in
Low-volume markets (player props) get less attention
Different books disagree — if one book offers +150 and another offers +120 on the same outcome, at least one of them is off
This is where the edge lives. When you can identify a bet where the sportsbook’s implied probability is lower than the true probability, you have a +EV opportunity.
+EV vs. “Sharp” Betting
These terms are related but not identical:
| Concept | Meaning |
|---|---|
| +EV Betting | Finding bets where your expected return is positive |
| Sharp Betting | Following line movement from professional bettors |
| Arbitrage | Exploiting price differences between books for guaranteed profit |
+EV is the broader strategy. It includes finding value through your own models, tracking line movement, or leveraging no-vig fair odds across multiple sportsbooks.
The Role of Win Percentage
Expected value depends entirely on knowing the true win probability of a bet. But how do you find it?
There are a few approaches:
No-vig fair odds: Strip the vig from sharp sportsbooks to estimate the true probability
Statistical models: Build or use models that project player/team performance
Market consensus: Compare odds across multiple books to find the market’s “true” price
Many +EV tools and services combine all three approaches to estimate probabilities and identify opportunities automatically.
Sample Size Matters
Here’s the most important thing to understand about +EV betting: it’s a long-term strategy.
You will lose individual bets. You’ll have losing days, even losing weeks. That’s variance. But if you consistently place +EV bets, the math works in your favor over hundreds and thousands of bets.
Think of it like a casino. The house doesn’t win every hand of blackjack — but they have a small edge on every hand, and over millions of hands, they always come out ahead.
+EV betting puts you on the house’s side of the equation.
Getting Started with +EV Betting
Ready to start? Here’s a simple process:
Compare odds across multiple sportsbooks
Calculate no-vig fair odds to estimate true probabilities
Find bets where the posted odds imply a lower probability than the true probability
Size your bets appropriately — don’t risk too much on any single wager
Track your results over time and trust the process
Key Takeaways
+EV betting means finding bets where you have an edge over the sportsbook
The math is simple: if your expected return per bet is positive, you’re +EV
It requires patience — variance means short-term results can look bad even when your strategy is sound
+EV tools automate the hard work of comparing odds and calculating fair value across sportsbooks
The bettors who win long-term aren’t the ones with the best “gut feel.” They’re the ones who understand expected value and stick to the math.
