Every line a sportsbook posts is, by definition, wrong. Built into every price is the bookmaker's margin — the vig — that ensures the house wins over time even if the public splits action perfectly. No-vig (devigged) fair odds are what the price would be if the book made zero margin. Learning to compute them is the difference between betting blind and betting with a fair-value benchmark.
Walk up to any moneyline in any sport and you'll find the same structural quirk: the two sides don't add up to a coin flip. A typical NFL game with two evenly matched teams isn't posted at +100 / +100 (a true coin). It's posted at −110 / −110. Convert both prices to implied probability and you get 52.38% on each side — sum 104.76%. That extra 4.76% above 100% is the sportsbook's hold. Take it out, and you reveal what the market is actually saying about who wins.
This guide walks through the math — with worked examples on a standard NFL moneyline, an MLB underdog/favorite pair, and a 3-way soccer market — then explains how sharp bettors use de-vigged fair odds to find +EV and why it's the single most useful price-transformation in the sharp-bettor toolkit.
Sportsbooks aren't charities. The vig is the price you pay for the privilege of placing a bet, baked silently into the odds so you don't notice it the way you'd notice a 5% transaction fee. On a balanced two-way market, the book mathematically wins regardless of which side hits — assuming action is balanced enough to use one side's losing stake to pay the other side's winning ticket.
Two ways to express the same margin, depending on whose perspective you're taking:
The numbers are the same; the framings differ. (See the Hold & Vig guide for the full breakdown.) The point for this article: every posted two-way line carries this baked-in margin. Until you strip it out, you're not looking at the market's probability estimate — you're looking at the market's probability estimate plus a tax. Devigging is how you separate the two.
The math is mechanical once you have the implied probabilities. Three steps:
1. Convert each side's American odds to implied probability.
2. Sum the implied probabilities across all sides. The total will exceed 100% — the excess is the vig.
3. Divide each side's implied probability by the sum. The result is that side's de-vigged probability. Convert back to American odds for the fair-odds price.
For positive American odds, implied probability = 100 / (odds + 100). For negative American odds, implied probability = |odds| / (|odds| + 100). That's all you need for the conversion. Run the math by hand or plug numbers into the No-Vig Calculator — same answer either way.
The canonical case. Two evenly matched teams in a coin-flip game, both priced at −110.
Side A: −110 → implied 110/210 = 52.38%
Side B: −110 → implied 110/210 = 52.38%
Sum: 104.76% — 4.76% over 100% is the vig
Side A devigged: 52.38% / 104.76% = 50.00% → fair odds: +100
Side B devigged: 52.38% / 104.76% = 50.00% → fair odds: +100
Hold (book's take): 1 − (1/1.0476) = 4.55% of total handle
The fair price is +100 / +100 — a true coin flip in dollar terms. The posted price of −110 / −110 charges you 4.55 cents on every dollar wagered for the privilege of taking a coin flip you could resolve at home for free. That's the vig you have to beat before any of your edge starts to compound.
Two-way markets aren't usually symmetric. A heavy favorite vs underdog produces a different shape. Suppose a sportsbook hangs:
Dodgers: −165 → implied 165/265 = 62.26%
Rockies: +140 → implied 100/240 = 41.67%
Sum: 103.93% — 3.93% over 100%
Dodgers devigged: 62.26% / 103.93% = 59.91% → fair odds: −149
Rockies devigged: 41.67% / 103.93% = 40.09% → fair odds: +149
Hold: 3.78% — a touch lower than the symmetric coin-flip case
Two things to notice. First, the de-vigged fair odds are symmetric: −149 / +149. Without the vig, the bet would pay you exactly as much to back the dog as it costs you to back the favorite, scaled by their respective probabilities. Second, the hold is slightly lower (3.78%) than the −110/−110 case (4.55%). Lopsided markets often carry less hold than balanced ones — books shade the favorite less aggressively because they don't need as much vig to discourage action on a price the public already considers chalk.
Now the practical question: if your model puts the Dodgers at 64%, the de-vigged fair price says the market thinks 59.91%. You have ~4 percentage points of edge against the de-vigged number — meaningful. If you'd compared your 64% against the raw posted price of −165 (implying 62.26%), you'd have thought the edge was only ~1.7 points and possibly passed. Devigging tells you what the market actually thinks the probability is. The posted price is just that estimate plus a tax.
De-vig math works for any number of outcomes. Three-way soccer markets (home win / draw / away win) all sum to one across the de-vigged probabilities — same as two-way markets. Suppose a soccer match is hung at:
Home: +110 → implied 100/210 = 47.62%
Draw: +245 → implied 100/345 = 28.99%
Away: +250 → implied 100/350 = 28.57%
Sum: 105.18% — 5.18% over 100% (3-way markets carry more vig than 2-way)
Home devigged: 47.62% / 105.18% = 45.27% → fair odds: +121
Draw devigged: 28.99% / 105.18% = 27.56% → fair odds: +263
Away devigged: 28.57% / 105.18% = 27.16% → fair odds: +268
The 5.18% vig on this 3-way market is fatter than the 4.55% on a typical 2-way moneyline. That's structural: more outcomes mean more opportunities for the book to hide margin in any one price. Soccer 1X2 markets routinely hold 5–7% in retail books. Pinnacle and similar sharp books hold 1.5–3% on the same matches — one of several reasons sharp bettors use sharp-book lines as the de-vigged baseline rather than retail prices.
The de-vigged number isn't just a curiosity. It's the input that drives every downstream sharp-betting decision. Three concrete uses:
Before placing a bet, compare your model's win probability to the de-vigged market probability on the same outcome. If your model says 55% and the de-vigged market says 52%, you have ~3 points of edge against the consensus. If your model says 55% and the de-vigged market says 56%, the market disagrees with you — pass, because the consensus across thousands of bettors is more likely right than your single estimate is. The raw posted price doesn't tell you this; the de-vigged price does.
The most replicable +EV strategy in retail betting: use Pinnacle (or another sharp book) to compute the de-vigged fair odds, then check whether soft retail books (DraftKings, FanDuel, BetMGM) are posting prices that diverge enough from that fair line to be worth taking. Soft books often move slower than sharp books — especially on lower-volume markets or during off-hours — and the gap between their posted price and the sharp-book fair price is a measurable +EV opportunity.
Closing line value is most rigorously measured against the de-vigged closing line, not the raw closing price. If you take a bet at +130 and the closing posted price is +120 (a 4.4pp implied-probability gain), that looks like solid CLV. But if the closing line de-vigs to a fair price of +128, your taken price of +130 was only a marginal improvement — not the substantial CLV the raw comparison implied. Sharp CLV trackers always devig before comparing.
No-vig odds (also called devigged or fair odds) are sportsbook prices with the bookmaker's profit margin mathematically removed. They represent the market's true estimate of each outcome's probability. Posted lines always sum to more than 100% implied probability across all outcomes — the excess is the vig. Stripping it out gives you fair odds: what the price would be if the book made zero margin.
Convert each side's American odds to implied probability, sum the implied probabilities (the sum will exceed 100% because of vig), then divide each side's implied probability by the total. The result is the de-vigged probability for that side. Convert back to American odds for the fair-odds price. Our No-Vig Calculator does this in one click.
The vig is what you pay the sportsbook to take your bet. On a typical −110/−110 two-way market, vig is about 4.55% of total handle. You have to beat the vig before you make any profit — meaning your true win probability has to exceed the de-vigged market probability by a meaningful margin, not just the posted price. Sharp bettors compare their estimates to de-vigged fair odds, not to the raw posted prices.
Pinnacle (and similar sharp books) post lines with very low vig — often 2–2.5% on major-sport moneylines vs 4.5%+ at retail US books. Their lines are closer to no-vig fair odds without any math. Many sharp bettors treat Pinnacle's de-vigged consensus as the best available true-probability estimate, and use it to find +EV at softer retail books that haven't moved their prices yet.
The same de-vig math applies, but player-prop markets carry much wider vig (often 8–15%) and update slower than game markets. The de-vigged probability you compute on a player prop is a better estimate than the posted price, but it's still a less efficient market — both because props are lower-volume and because individual books don't shop them as competitively. The fair odds you derive are useful but should be treated as a starting point, not gospel.
The accuracy depends on the book you're devigging. Sharp-book lines (Pinnacle, Circa, Bookmaker) devig to nearly true probability — academic studies routinely find them within 1–2% of long-run actual outcomes. Soft retail-book lines devig to something more like "the market the public has been steered into," which can drift from true probability by 3–5% on bias-prone games (heavy public favorites, marquee teams). Sharps prefer sharp-book devigs as the baseline.