How do you devig sportsbook odds to find the fair price?
Convert both sides of a market to implied probabilities, then divide each by their sum. A -150/+130 market implies 60% and 43.5%, totaling 103.5%. Divide through: the fair probabilities are 58% and 42%, making the fair price about -138/+138. Any price better than fair is +EV.
Every +EV decision comes down to one comparison: the price you’re offered versus the price the bet is actually worth. The second number is the fair price, and devigging is how you find it. It takes two steps and a phone calculator.
Step one: turn both sides into probabilities
Take any market, both sides. Say a moneyline posted at -150 on the favorite and +130 on the dog.
Implied probability for a negative line is odds / (odds + 100): so 150/250 = 60%. For a positive line it’s 100 / (odds + 100): so 100/230 = 43.5%.
Add them: 60 + 43.5 = 103.5%. Real probabilities sum to 100. That extra 3.5% is the vig, the book’s fee, baked invisibly into both prices. We covered why that means -110 is never a coin flip.
Step two: rescale to 100
Divide each side by the total. Favorite: 60 / 103.5 = 58%. Dog: 43.5 / 103.5 = 42%.
Those are the market’s fair probabilities, and converting back gives fair odds of about -138 and +138. That’s the whole technique. The favorite posted at -150 is worth -138: you’re overpaying. If some other book posts that same favorite at -125, they’re paying you better than fair, and that’s a +EV bet before any boost even enters the picture.
Why this number runs the whole desk
When a book boosts a bet from +240 to +312, the boost is only worth something relative to the true odds. If the fair price is +250, the boosted +312 carries a real, measurable edge. If the fair price is +330, the “boost” still leaves you underpaid, and the flashy percentage was marketing. The fair price is the yardstick that separates those two cases, and devigging is where the yardstick comes from.
Every play the desk posts shows its fair odds next to the boosted price for exactly this reason. Not “trust me,” but “here’s the yardstick, check it.” The no-vig calculator runs steps one and two for you: both sides in, fair price out. And the boost EV calculator takes it from there: fair price plus boost in, edge out.
Where devigging gets honest people in trouble
Three failure modes worth knowing. First, devigging a soft book recovers a soft opinion: the fair price is only as sharp as the market you pulled it from, so use the highest-limit books and exchanges you can. Second, the simple method above spreads the vig in proportion to each side, and on lopsided markets (a -400 favorite) books actually shade the longshot side harder, so this method slightly flatters longshots. Third, thin markets move: a fair price on an obscure prop is an estimate with error bars, not a law of physics.
None of that breaks the method. It just means the fair price is the best available estimate, and the discipline is betting only when your edge is big enough to survive the estimate being a little off.
If you’d rather watch the method work than run it by hand, the free Discord posts one boosted play a day with the fair odds and edge already computed: join free. Check the math against the public ledger any time.
Quick answers
What does devigging mean in betting?
Removing the sportsbook's built-in fee (the vig) from a market to estimate the true probabilities. Both sides of a line always imply probabilities summing over 100%; the excess is the book's margin. Devigging rescales them to sum to 100%, which is the market's honest opinion.
What is the fair price of a bet?
The odds that would pay exactly in line with the true probability, with no fee attached. It's what a bet is worth, as opposed to what a book charges. Comparing a posted price to the fair price is the entire +EV decision: better than fair, bet it; worse, skip it.
Which odds should I devig from?
The sharpest market you can find, which usually means the books with the highest limits and the exchanges where real money sets the price. Devigging a soft book's line just recovers that book's opinion. The desk blends several sharp sources for exactly this reason.
Does devigging work on parlays and props?
Yes, one leg at a time: devig each leg, multiply the fair probabilities, and you have the parlay's fair price. That multiplication assumes the legs are independent, so it works across different games; same-game legs are correlated and need joint pricing. Props are often the most mispriced markets, but they're also thinner, so the fair number carries more uncertainty than a heavily-traded moneyline.
Wanna see which boosts cleared the bar today?
The bot checks every boost at every book each morning, posts the ones worth taking with the math shown, and grades everything in public. Watching is free.