No-Vig (Fair Odds) Calculator

The No-Vig Calculator strips the sportsbook’s margin out of any American-odds market, showing you the fair price and true probability behind a line like -150 or +130 so you can spot real value on NFL, NBA, MLB, or NHL bets.

What Is a No-Vig Calculator?

A no-vig calculator answers the question the raw price hides: after you remove the book’s margin, what chance does it really give each side? Every American-odds line already has the sportsbook’s built-in edge baked into it. Convert both sides of a two-way market to implied probability and add them up, and the total comes out above 100%. That extra percentage is the vig, the book’s cut for taking the bet. None of the implied probabilities on the board is the book’s honest estimate of what will happen; every one of them is inflated.

A no-vig calculator removes that inflation. It takes the implied probabilities from both sides of a market and rescales them proportionally so they sum to exactly 100%, producing the fair, no-vig probability for each outcome, then converts those fair probabilities back into American odds for the favorite and the underdog.

That fair line matters because it is the benchmark serious bettors compare every price against. A sportsbook’s price tells you what you can bet at; the no-vig price tells you what the market actually thinks will happen. Find a book offering better odds than the fair no-vig number on a side, and that bet carries positive expected value.

How No-Vig Odds Are Calculated

The calculation runs in three steps, starting with the same implied-probability conversion used everywhere in sports betting. For a favorite priced at minus odds, implied probability equals the odds figure divided by the odds figure plus 100; for an underdog priced at plus odds, it equals 100 divided by the odds figure plus 100. On a market priced -150 on the favorite and +130 on the underdog, that math turns -150 into a 60.0% raw implied probability and +130 into a 43.48% raw implied probability.

Step two is to add those raw implied probabilities together. On the -150 / +130 market, 60.0% and 43.48% sum to 103.48%, meaning the book has built in a 3.48% vig. Every two-way market you convert this way will sum to something above 100%; the size of the overshoot is the size of the vig.

Step three is the rescale that gives the method its name. Divide each side’s raw implied probability by the market total, and the two numbers now sum to exactly 100%. On the -150 / +130 market, that rescale turns 60.0% into a fair 58.0% and turns 43.48% into a fair 42.0%. Converting those fair probabilities back into American odds produces the fair price for each side: -138 for the favorite and +138 for the underdog. That -138 / +138 line is the no-vig price, the market’s honest estimate with the sportsbook’s cut removed.

What the Calculator Shows You

For each side of the market you enter, the calculator returns four figures: the raw American odds you typed in, unchanged; the raw implied probability that price carries, which still includes the book’s margin; the fair, rescaled probability once the vig has been proportionally stripped out and every side’s chance sums to exactly 100%; and the fair no-vig American odds that correspond to that rescaled probability. Alongside the per-side figures, the calculator also shows the market total: the sum of every side’s raw implied probability before rescaling, which tells you exactly how much vig the book has built into that line. Comparing your sportsbook’s actual price against the fair odds the calculator produces is how you judge whether a bet is worth making.

Worked Example

Take a two-way NFL moneyline priced -150 on the favorite and +130 on the underdog. Start with the favorite: a price of -150 converts to a raw implied probability of 60.0%. Now the underdog: a price of +130 converts to a raw implied probability of 43.48%.

Add the two raw implied probabilities together: 60.0% plus 43.48% comes to a market total of 103.48%. Since a fair, two-outcome market should sum to exactly 100%, that extra 3.48% is the vig the sportsbook has priced into this line.

To find the fair numbers, rescale each side by dividing it by the market total of 103.48%. The favorite’s 60.0% becomes a fair probability of 58.0%, and the underdog’s 43.48% becomes a fair probability of 42.0%. Check the math: 58.0% and 42.0% now sum to exactly 100%, confirming the vig has been fully removed.

Converting those fair probabilities back into American odds gives the fair price for each side: -138 for the favorite and +138 for the underdog, the line this market would show at a sportsbook with zero margin.

The payoff of doing this work is a benchmark for value. The raw board price was -150 on the favorite, but the fair price is only -138. Any sportsbook offering the favorite at better than -138 is giving you more than the fair line implies, which is where value lives. The same logic runs in reverse for the underdog: fair value sits at +138, so any price better than that on the underdog side is worth a second look.

No-Vig Fair Probability by Market Price

The rescale above works the same way on any two-way market, and the vig baked in varies by how the book prices the line. A near pick’em market like -110 / -110 can carry a higher raw sum than a lopsided line, even though each side’s percentage of that vig differs. The table below shows the raw market total and the resulting fair probability for the favorite and the underdog across four price combinations.

Raw vs Fair Price on the -150 / +130 Market

This table lays the raw and fair figures for the -150 / +130 market side by side: the odds you’d actually bet at, the implied probability those odds carry, the rescaled fair probability, and the fair American odds that probability converts back to.

Where the Simple No-Vig Method Falls Short

The proportional rescale used above is the standard approach, but it isn’t the only one, and it carries a small, known bias on lopsided markets. It shaves a little too much probability off big favorites and gives back a little too little to long-shot underdogs. More advanced approaches, such as the Shin method and the logarithmic method, correct for that skew mathematically. For typical two-way US lines, though, the simple rescale is close enough to be genuinely useful, and it’s the version most bettors reach for first.

The more important point isn’t which formula you use - it’s what the fair number is for. The sharpest fair line in any market is usually the closing price at a low-vig sportsbook, once all the information that will move the market has moved it. Beating that closing line consistently, known as positive closing line value, is the strongest evidence a bettor is genuinely finding value rather than running hot.

Three-way markets work on the same principle: divide all three implied probabilities by their combined total instead of just two. But the wider a market’s vig runs, the more the fair estimate can drift from the true chance, so pulling your raw prices from a low-vig book gives you a truer fair line before you ever rescale it.

When the No-Vig Line Makes Sense

The no-vig line earns its keep any time you need a true probability rather than a bettable price. Before placing a wager, converting a market to its fair odds tells you whether the number you’re being offered is actually generous or just looks that way next to a round number like -110. A favorite at -150 might feel expensive, but the calculator shows the fair price is -138, so anything you can find better than -138 elsewhere is real value, not a coincidence of one book’s house line.

It’s also the right tool for comparing prices across sportsbooks. Two books can quote the same favorite at different odds because they carry different amounts of vig, not because they disagree about who’s going to win. Stripping the vig from each book’s line lets you compare their honest opinions instead of numbers each distorted by a different margin.

Where it makes less sense is as a standalone betting strategy. The no-vig price is a reference point, not a bet you can place - no sportsbook offers a zero-vig line as a real option. It’s most useful layered on top of other work: tracking closing line value over time, building a personal power rating to compare against the market’s fair number, or deciding which of several available prices on the same game is better. Bettors chasing quick edges on one game get more out of shopping lines directly; bettors proving their long-run edge is real get more out of tracking no-vig performance across many bets.

Common Mistakes

Treating a raw implied probability as the fair chance is a common error, since it still holds the vig and overstates every side’s likelihood. Removing the vig from only one side instead of rescaling every outcome breaks the math and leaves the total above 100%. Using a high-vig book’s line as the fair benchmark instead of a low-vig source skews the fair number away from the true chance. Finally, assuming the simple rescale is exact on heavily lopsided favorites ignores the known bias that methods like Shin are built to correct.

No-Vig Fair Price vs Raw Price

The raw price is what you can actually bet, while the no-vig fair price is the benchmark you measure it against. The table below sums up the difference, using the favorite side of the -150 / +130 example.