How +EV actually works
Forget the jargon. +EV just means: the odds in front of you are better than what the bet is actually worth. Here's how anyone can check that — and how we do it under the hood.
Step 1: Odds → implied probability
Every set of odds converts to a probability. American +150 = 40%. -110 = 52.4%. That's what the price is saying about how often the bet should win.
Step 2: Add both sides — find the vig
A two-way market should sum to 100%. If both sides of a coin flip are priced at -110, the implied probabilities add to 104.8%. That extra 4.8% is the sportsbook's vig.
Step 3: Devig → fair odds
Scale both probabilities back to 100%. Now you have the market's true belief — the fair price. Compare it to what you're being offered. If your price implies a lower probability than the fair price says, you have edge.
Step 4: Calculate EV
EV = (fair win % × profit) − (fair loss % × stake)
Positive number? +EV. The bigger the edge, the better the long-run return. That's it — that's the whole engine behind every grade on this site.
The EV calculator does all four steps in one input. The Boost Analyzer pulls live market data so you don't have to look up fair odds yourself.
Frequently asked questions
What does +EV mean in sports betting?
+EV (positive expected value) means the odds you're getting are better than the bet's true probability. Over the long run, +EV bets make money regardless of whether any single bet wins or loses.
How do you calculate expected value on a bet?
EV = (probability of winning × profit if you win) − (probability of losing × stake). If the result is positive, the bet is +EV. To get the true probability, you devig the market: take the implied probabilities from both sides, then scale them so they sum to 100%.
What's the difference between fair odds and the odds I see?
Fair odds are what the bet should pay with zero house edge. The odds posted at a sportsbook include vig (typically 4–7%), which is the book's built-in profit margin. Fair odds are always longer (better for you) than posted odds.
How much edge do I need for a bet to be worth it?
Most sharp bettors target 2% or more edge over fair value. 5%+ is rare and strong. Anything under 1% gets eaten by variance and the inevitability of getting limited if you bet too aggressively.
Can a -EV bet ever be a good idea?
Only when paired with a promo or boost that flips the EV positive — e.g. a risk-free bet token, deposit match, or odds boost large enough to beat fair value. The bet itself isn't profitable; the promo is.