To remove the vig from a betting market, convert the odds on every side to implied probabilities, add them up, and divide each side's probability by that total. The results add up to exactly 100% and are the market's no-vig fair probabilities; convert them back to odds to get the fair price. This is called devigging, and the fair price it gives is an estimate of the true chances, not a fact about the outcome.
How it works
A sportsbook prices both sides so their implied probabilities add up to more than 100%. The excess is the vig, also called juice or margin. Devigging scales it away.
- Negative American odds:
implied probability = |odds| / (|odds| + 100) - Positive American odds:
implied probability = 100 / (odds + 100) fair probability = side's implied probability / sum of every side's implied probabilityfair decimal odds = 1 / fair probability
Even market: -110 / -110. Each side implies 110 / 210 = 52.38%. Together they add up to 104.76%, an overround of 4.76 points. Dividing each side by 1.0476 gives 50% and 50%: a fair price of +100 (decimal 2.00) on both sides.
Lopsided market: -150 / +130.
- Implied probabilities. -150 is
150 / 250 = 60.00%. +130 is100 / 230 = 43.48%. - Total.
60.00% + 43.48% = 103.48%, an overround of 3.48 points. - Fair probabilities.
60.00 / 103.48 = 57.98%and43.48 / 103.48 = 42.02%. They add up to 100%. - Fair odds. Favorite:
−57.98 / 42.02 × 100 = −138, or decimal1 / 0.5798 = 1.725. Underdog:57.98 / 42.02 × 100 = +138, or decimal1 / 0.4202 = 2.380.
| Favorite | Underdog | |
|---|---|---|
| Offered odds | -150 | +130 |
| Implied probability | 60.00% | 43.48% |
| No-vig probability | 57.98% | 42.02% |
| Fair odds | -138 (1.725) | +138 (2.380) |
The fair price is what makes the number useful. If another book offers the underdog at +145 (decimal 2.45), that beats the fair +138: 0.4202 × 2.45 − 1 = 0.029, about +2.9% expected value against this estimate. That is a positive EV bet, which What is positive EV betting? explains.
Methods give slightly different answers
The method above is proportional, also called multiplicative: it takes vig from each side in proportion to its implied probability. Other methods split the margin differently. The additive method subtracts an equal share of the overround from each side. Here that is 60.00 − 1.74 = 58.26% and 43.48 − 1.74 = 41.74%, a fair price of about -140 / +140 instead of -138 / +138. Power and probit methods also tend to take more of the margin from the longshot. On near-even markets the methods barely differ; on long shots the gap grows.
How to do it
- Get every side of one market. Same game, same line, prices quoted at the same moment. A -3 on one side and a +3.5 on the other are not one market.
- Convert each price to implied probability. The implied probability calculator does this for American or decimal odds.
- Add them up. The amount over 100% is the overround. The hold calculator shows the hold and the overround for a two-way market.
- Divide each side by the total. The results are the fair probabilities, and they add up to 100%.
- Convert back to odds.
1 / fair probabilitygives fair decimal odds. Convert to American if you prefer. - Compare. A price elsewhere that pays more than the fair odds is +EV against this estimate.
For a three-way market, such as a soccer result with a draw, do the same with all three outcomes: add the three implied probabilities and divide each one by the total.
Using Unjuiced
The no-vig calculator does steps 2 to 5. Enter the odds for both sides of a two-way market and it returns the fair odds and fair probability for each side, using the proportional method above. It is free and needs no account, like every Unjuiced calculator.
To do this across many markets at once, Positive EV devigs both sides of a sharp market (Pinnacle by default) and ranks prices at other books by EV % against the fair odds. You can pick the devig method: Power, Multiplicative, Additive or Probit. Positive EV is included with Pro and Syndicate; Free and Scout accounts see a limited preview.
Mistakes to avoid
- Devigging one side. You can't remove the vig from a single price; you need every side of the market. A lone -150 tells you its break-even rate, 60%, not the fair chance.
- Mixing lines or moments. Prices from different lines, or from different times, don't form one market. Using the best price on each side from two books is fine when both are live at once; it estimates the wider market's fair price rather than one book's.
- Starting from a weak market. Devigging a high-hold market at a book that is slow to move gives a fair price only as good as those prices. Most bettors devig a sharp, low-hold market and compare the rest against it.
- Treating fair odds as truth. A no-vig price is the market's estimate with the margin removed. The choice of method alone moved this example by two cents on each side, and the gap is bigger on long shots.
- Missing an arbitrage. If the two sides add up to less than 100%, usually because they come from different books, there's no vig to remove. Betting both sides in the right amounts returns more than the total stake whichever side wins, if both bets are accepted at those prices. See how to use the Arbitrage tool.
Questions
What does no-vig mean in betting?
No-vig odds are a market's prices with the sportsbook's margin removed, so the implied probabilities of all sides add up to exactly 100%. They are an estimate of each side's fair price, and they are the benchmark positive EV bettors compare other prices against.
How do you remove the vig from American odds?
Convert each side to implied probability (for negative odds, the odds' absolute value divided by that value plus 100; for positive odds, 100 divided by the odds plus 100), add the sides together, and divide each side by that total. For -110 / -110, each side is 52.38%, the total is 104.76%, and each fair probability is 50%, or +100.
What is the difference between vig, hold and overround?
Vig is the margin a sportsbook builds into its prices. Overround measures it as how far the sides' implied probabilities add up above 100%: -110 / -110 totals 104.76%, an overround of 4.76 points. Hold measures it as the share of money the book keeps when action is balanced on both sides, 1 − 1 / 1.0476, or about 4.55% for the same market.
Which devig method is most accurate?
No method is right for every market. The proportional, or multiplicative, method is the simplest and a common default; power, additive and probit methods shift more of the margin onto the longshot, which can fit lopsided markets better. On near-even markets they give almost the same answer.
Is there a free no-vig fair odds calculator?
Yes. Unjuiced's no-vig calculator is free and needs no account. Enter the odds for both sides of a two-way market and it returns the fair odds and fair probability for each side.