Devigging means removing the bookmaker's margin (the vig) from a betting line, so you can see the probabilities the bookmaker is really working with. You do it in three steps: turn each price into an implied probability, add the probabilities together, then divide each one by that total. What you get is the fair price, also called the no-vig price.
Take a point spread priced at -110 (1.91 in decimal odds) on both sides. Each price implies 52.38%. Together that is 104.76%, and the extra 4.76% is the margin. Divide 52.38 by 104.76 and you get 50%. The fair price on each side is +100 (2.00).
That fair price is the number you compare every other price with. Below is the method for two-way and three-way markets, the Google Sheets formulas, and the places where devigging can mislead you.
What does devigging actually mean?
A sportsbook does not offer fair odds. It shortens every price a little, so the implied probabilities of all the outcomes add up to more than 100%. The amount over 100% is the margin. You will also see it called vig, juice or overround. They all mean the same thing.
Devigging takes that margin back out. What is left is a set of probabilities that add up to exactly 100%. That is the bookmaker's real opinion of the game.
The bookmaker margin lesson shows where the margin comes from and what it costs you over many bets.
How do you devig a two-way line step by step?
Here is a moneyline with a favorite at -150 (1.67) and an underdog at +130 (2.30).
Step 1: turn each price into an implied probability.
- Decimal odds: 1 / odds
- Negative American odds: odds / (odds + 100), using the number without the minus sign
- Positive American odds: 100 / (odds + 100)
So -150 implies 150 / 250 = 60.00%, and +130 implies 100 / 230 = 43.48%.
Step 2: add them. 60.00% + 43.48% = 103.48%. The margin on this line is 3.48%.
Step 3: divide each probability by the total.
- Favorite: 60.00 / 103.48 = 57.98%
- Underdog: 43.48 / 103.48 = 42.02%
Step 4: turn the fair probabilities back into prices. Fair decimal odds are 1 / probability.
| Side | Sportsbook price | Implied probability | Fair probability | Fair price |
|---|---|---|---|---|
| Favorite | -150 (1.67) | 60.00% | 57.98% | -138 (1.72) |
| Underdog | +130 (2.30) | 43.48% | 42.02% | +138 (2.38) |
The bookmaker thinks the favorite wins about 58% of the time, not 60%. The difference is what you pay to place the bet.
How do you devig a three-way market like a soccer match?
The same way. You only have three numbers to add in place of two.
Take a match priced at 2.10 (+110) for the home win, 3.40 (+240) for the draw and 3.60 (+260) for the away win.
| Outcome | Sportsbook price | Implied probability | Fair probability | Fair price |
|---|---|---|---|---|
| Home win | 2.10 (+110) | 47.62% | 45.43% | 2.20 (+120) |
| Draw | 3.40 (+240) | 29.41% | 28.06% | 3.56 (+256) |
| Away win | 3.60 (+260) | 27.78% | 26.50% | 3.77 (+277) |
The implied probabilities add up to 104.81%, so the margin is 4.81%. Each fair probability is the implied probability divided by 104.81%.
How do you set up a devig calculator in Google Sheets?
With four short formulas. Put the American odds for the two sides in cells A2 and A3.
- Decimal odds, in B2:
=IF(A2>0, A2/100+1, 100/ABS(A2)+1) - Implied probability, in C2:
=1/B2 - Fair probability, in D2:
=C2/SUM(C$2:C$3) - Fair decimal odds, in E2:
=1/D2
Copy all four formulas down one row so that row 3 covers the other side. If you want the fair price in American odds as well, add =IF(E2>=2, (E2-1)*100, -100/(E2-1)) in F2.
For a three-way market, add the third outcome in row 4 and change the range in the D column to C$2:C$4.
The fair odds calculator lesson lets you play with the same numbers before you build the sheet.
Which devig method should you use?
The method above is called the proportional method. It assumes the bookmaker spread the margin across the outcomes in proportion to their probability. On lines close to even money, such as most spreads and totals, that assumption works well.
On a lopsided line it works less well. Research on betting markets has found for decades that longshots carry more of the margin than favorites. It is known as the favorite-longshot bias. The proportional method ignores it, so it tends to make the underdog look a little better than it is.
The power method corrects for that. It raises each implied probability to the same power, chosen so that the results add up to exactly 100%. Here are both methods on a favorite at -400 (1.25) against an underdog at +300 (4.00):
| Method | Favorite, fair probability | Favorite, fair price | Underdog, fair probability | Underdog, fair price |
|---|---|---|---|---|
| Proportional | 76.19% | -320 (1.31) | 23.81% | +320 (4.20) |
| Power | 78.24% | -359 (1.28) | 21.76% | +359 (4.60) |
The two methods disagree by 2 percentage points on the underdog. That is enough to change a decision. If another sportsbook offers that underdog at +330 (4.30), the proportional method calls it a value bet and the power method calls it a losing bet.
I would use the proportional method for anything near even money. For a big favorite against a big underdog, treat the proportional number for the underdog as the best case, and check it with the power method before you bet.
Which sportsbook's line should you devig?
The sharpest one you can see. Devigging gives you one bookmaker's opinion, so the opinion has to be worth something.
A sportsbook with a low margin and high limits takes large bets from the best bettors in the world, and it moves its price when they bet. Its line is corrected all day. A recreational sportsbook moves more slowly and copies more, so its devigged price tells you less. Pinnacle's closing line is the reference price most serious bettors use.
Then you compare. Say the sharp line is the one from the example above, and its fair probability for the favorite is 57.98%. Your own sportsbook offers that favorite at -130 (1.77).
- Expected value at -130 (1.77): 0.5798 x 1.769 - 1 = +2.6%
- Expected value at -140 (1.71): 0.5798 x 1.714 - 1 = -0.6%
At -130 you have a bet. At -140 you do not. The expected value lesson shows what a gap like that is worth over many bets.
That reference is the one I measured my own bets against. Across my NFL model bets, checked bet by bet against Pinnacle's closing line, closing line value came out at +3.81% across one full season and +4.25% on the 2025/26 snapshot. Closing Line Value Explained shows how to track it for your own bets.
What can devigging not tell you?
Four things.
- The truth. A devigged price is the bookmaker's estimate with the margin taken out. A sharp bookmaker is right more often than anyone else, and it is still wrong sometimes.
- The price later. A line you devig on Tuesday is the market's opinion on Tuesday. An injury report can move it before the game, so use a price from the same moment you bet.
- How the margin was spread. Every method is an assumption about that. On even lines the assumption hardly matters. On lopsided lines, and on futures with many teams, it matters a lot.
- What you think. Devigging tells you what the market thinks of a game. It does not give you an opinion of your own, and without one you can only follow the market from one sportsbook to the next.
That last point is the reason to build a model, even a simple one. The devigged price is one number and your own price is the second. The bets worth looking at are the games where the two are far apart.
FAQ
Is devigging the same as finding the no-vig line?
Yes. Devigging, removing the vig, removing the juice and finding the no-vig line are four names for the same calculation. In every case you take a bookmaker's prices, turn them into implied probabilities, and scale them down so they add up to exactly 100%. The result is called the fair price, the no-vig price or the true odds. The word "true" is a little generous. It is the bookmaker's own estimate with the margin taken out, which makes it a very good reference and not a guarantee.
How much vig is on a standard -110 line?
A line with -110 (1.91) on both sides has a margin of 4.76%. Each side implies 52.38%, the two add up to 104.76%, and the part above 100% is the margin. That is why you need to win 52.38% of your bets at -110 to break even. A reduced-juice line of -105 (1.95) on both sides adds up to 102.44%, so the margin is about half as big. Over a few hundred bets that difference is real money, and it is the reason the price you take matters as much as the side you pick.
Can you devig a line when only one side is posted?
No. You need the price of every outcome in the market, because the margin only shows up when you add all the implied probabilities together. With one price you cannot tell how much of it is probability and how much is margin. This comes up often with player props, where some sportsbooks post only the over. In that case, find another sportsbook that posts both sides of the same prop and devig that line. If nobody posts both sides, you do not have a fair price, and it is better to pass than to guess.
Does devigging work for player props and futures?
It works, but with a bigger error than on main lines. Props and futures usually carry a higher margin than spreads, totals and moneylines, and limits are lower, so the price is corrected less often by sharp bettors. On futures with many teams, the way the margin is spread across the field is unknown, and the proportional method can be far off for the longshots. Use the devigged number as a rough guide in these markets, and ask for a bigger gap before you call something value.
Is the devigged price the true probability?
No. It is the bookmaker's estimate of the probability, with the margin removed. For a sharp sportsbook close to game time that estimate is the best public number there is, which is why bettors use it as a reference. It is still an estimate. It can be wrong about one game, and it depends on the method you used to remove the margin. Treat it as the market's opinion, measured as well as it can be measured, and compare your own number with it.
Do I still need my own model if I can devig a sharp line?
Yes, if you want to do more than follow the market. A devigged sharp line lets you find sportsbooks that are slow to move, and that is a real way to bet. It also means your only edge is speed, and you never learn why a price is right or wrong. A model, even a simple one in Google Sheets, gives you a second number. When your number and the devigged price agree, you pass. When they are far apart, you have a game worth a closer look, and a reason for the bet that you can check later.
If you want the same price-first logic applied to a single game for you, that is what the AI Betting Assistant does. If you would rather work from a finished sheet than build your own, my models are on the models page.
Where do you start if you want a number of your own?
Devigging gives you the market's number. The other half is a number you made yourself. If you want to be walked through your first model, from a blank spreadsheet to a price of your own, that is what The Ultimate Modern Bettor's Toolkit is for.
$27, one payment. It includes the +EV betting model spreadsheet, a 45-minute video training that builds your first model with you, and the four-bucket staking system. 30-day money-back guarantee.
MB built Underdog Chance around one idea: make your own number first, then bet only when the price beats it. Over the last 20+ years his simple, probability-based Google Sheets models have helped thousands of bettors stop following picks and start pricing bets for themselves.
Last updated: 9 October 2026