Book margin: 4.76%
| Outcome | Fair probability | Fair odds | Stake split |
|---|---|---|---|
| Outcome 1 | 50.00% | +100 | 50.00 |
| Outcome 2 | 50.00% | +100 | 50.00 |
Returns 95.45 on 100.00 — yield -4.55% (profit ÷ stake).
No-vig calculator: what your odds look like without the bookmaker's cut
The calculator above strips the bookmaker's margin out of any two-way or three-way market and returns the fair odds and true implied probability for each outcome. Type the odds exactly as your sportsbook shows them — American, decimal or fractional — and the results update as you type. Nothing is uploaded and nothing is stored; the math runs in your browser.
One thing this page does that most no-vig tools do not: it tells you which devig method it is using, and lets you switch. Different calculators quietly use different formulas and return different fair prices for the same market. The method is part of the answer, so it belongs on the surface.
How the no-vig calculation works
Every price implies a probability: decimal odds of 1.91 imply 1 ÷ 1.91, which is 52.36%. Add the implied probabilities across all outcomes of one market and a fair book would sum to exactly 100%. A real sportsbook's sum is higher — at the NFL's standard price of -110 on both sides, the two probabilities add to 104.76%. That extra 4.76% is the vig: the bookmaker's margin, charged before the game even starts.
Removing it means scaling each probability back so the market sums to 100% — that is the entire no-vig formula: divide each implied probability by the market total. With the multiplicative method, -110/-110 devigs to a fair 50.00% each side — fair odds of +100. Your book sold you a coin flip at -110; the fair price of a coin flip is +100. The difference is what you paid.
The same arithmetic exposes the rare opposite case. If odds across outcomes imply less than 100% — say 2.10 and 2.05, which sum to 96.40% — the market is underround: an arbitrage. Staking 49.40 and 50.60 out of 100 returns 103.73 whichever side wins, a 3.73% yield on stake. This calculator reports that yield as profit divided by stake and says so, because some tools divide by payout instead and print a smaller number for the identical position.
Multiplicative vs additive: why calculators disagree
Feed -120/+100 into the market's best-known no-vig calculators and you will get two different answers. OddsJam and TheRundown return 52.17% for the favorite (multiplicative); Unabated returns 52.28% (additive). We operated all of them side by side in August 2026 and only one tool in the cohort — BetBurger — discloses which formula it is running. Neither answer is wrong; they are different models of where the bookmaker hides its margin. But a fair price whose method is secret is only half an answer.
Whichever name you search it under — devig calculator, de-vig tool, no-vig calculator — the operation is the same. Multiplicative (also called proportional) scales every outcome by the same factor and is the industry default; it assumes the vig is spread in proportion to each price. Additive subtracts an equal share of the overround from every outcome, which shifts more of the correction onto longshots — and on extreme longshots it can break down entirely, which this calculator reports as an error instead of printing a negative probability.
For most two-way markets the difference is small but real, and for sharp bettors comparing lines it compounds. The same goes for arb math: on the identical 2.10/2.05 position, surebet.com, BetBurger and TheRundown all report a 3.73% yield while OddsJam prints 3.60%, because it divides profit by payout instead of stake. Whichever definitions you use, use them knowingly. That is the whole reason the switches are on this page.
What fair odds are for
A no-vig price is a benchmark — the vig-free odds a fair book would quote. If the fair probability of a side is 50.00% and a book offers you +105, you are being paid better than fair; at -110 you are paying a tax. Line shoppers use fair odds to find which book is cheapest on a given market, and modelers use them as the market's true opinion, stripped of its sales fee.
The benchmark also makes exchange pricing legible. On a betting exchange, prices come from traders backing both sides against each other, so there is no bookmaker margin built into the odds at all — the number this calculator removes simply is not there. OVERDOG routes orders to Polymarket's markets at those exchange prices, settled in a dollar-stable unit on Polygon. The costs are disclosed together and up front: a flat 1% OVERDOG fee plus Polymarket's own fees. Compare that to the margin you just measured in your own book's odds and the argument makes itself.
FAQ
What is vig in betting?
Vig (vigorish, juice, margin, overround) is the bookmaker's fee baked into the odds. Add up the implied probabilities of every outcome in one market: the amount above 100% is the vig. At -110/-110 it is 4.76%.
How do you calculate no-vig odds?
Convert each price to an implied probability, then scale the probabilities so they sum to 100%. With the multiplicative method each probability is divided by the market total; the fair odds are the reciprocal of the fair probability. This calculator does both steps and shows the method.
Why do different no-vig calculators give different answers?
They use different devig methods — usually multiplicative or additive — and most do not say which. On -120/+100 the two methods return 52.17% and 52.27% for the same favorite. This calculator lets you switch between them so you always know which model you are reading.
Are exchange odds really vig-free?
The price itself carries no bookmaker margin, because it is set by traders on both sides rather than by a book protecting a profit. Fees exist and are charged separately and visibly — on OVERDOG that is a flat 1% fee plus Polymarket's own fees — instead of being hidden inside the odds.