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No-Vig Fair Odds Calculator
Every two-sided market carries the book's margin. Enter both prices and this strips it out: the estimated fair odds, the no-vig win probability, and how much hold you were being charged.
Use both sides of the same market at the same book: Over/Under, Team A/Team B, Yes/No. A sharp book's prices give the best proportional estimate — it's an estimate, not gospel.
This is the same number the Lab computes for every prop on tonight's board. See tonight's, or take the fair odds to the Profit Boost EV Calculator if you're pricing a boost.
How the math works
Convert both prices to implied probability and they add up to more than 100%. That extra is the book's margin. Divide your side by the total and the margin is gone:
fair probability = your implied % ÷ (your implied % + other side implied %)
Worked example: −110 / −110 on a spread. Each side implies 52.4%, totalling 104.8%. Your side's fair probability is 52.4 ÷ 104.8 = 50%, which is +100. The book sold you a coin flip at −110 and kept the difference. This proportional method is the standard two-sided devig, and it's the first step behind every price the Lab publishes. The full method, including when it can mislead you, is in how to devig odds.
No-vig questions
What is a no-vig (fair) price?
The odds a bet would have if the book took no margin: the market's honest estimate of the probability. It's the yardstick every bet should be measured against, because a bet only has edge if the price you get beats the fair price.
Why do fair odds matter for profit boosts?
A boost is only worth something if it lifts your payout above the fair price. Boosting a bad price can still leave you below fair. Fair odds in, boost on top, and the boost EV calculator tells you if the result clears zero.
Which book's prices should I use?
The sharpest market you can see, ideally where limits are high and lines move fast. Soft books copy sharp books, not the other way around. Averaging two or three books' devigged numbers is even better, which is what the Lab does with a full consensus pull.
Want this run for you every morning?
The Lab devigs multi-book consensus on every prop on the board, every day, and publishes what clears the bar, wins and losses both.