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No Vig Calculator (Devig)
Strip sportsbook vig from a two-way or N-way market. Paste American odds for each outcome and get the fair probability, fair American line, fair decimal, and the book's overround in one read.
No-Vig Odds Calculator
Remove bookmaker hold from a 2-way or 3-way market, recover fair probability, and compare your model to the no-vig line.
What this calculator does
Sportsbooks don't publish probabilities — they publish prices. Every price has the book's margin baked in, called the vig (vigorish, juice, hold, overround). On a standard -110 / -110 NFL spread, the book is taking roughly 4.76% off the top: bet $100 to win $90.91 per side, lose either way and the book pockets the difference. The no-vig price strips that margin out so you can compare the book's true probability estimate against your own model.
Worked example: NFL spread
Suppose the Chiefs are -3.5 (-110) against the Bills at +3.5 (-110). Both sides imply 52.38% probability. Their sum is 104.76% — the book's overround. The vig is 4.76%.
Devigging proportionally: each fair probability is 52.38 / 104.76 = 50.00%. The fair line both ways is +100 (decimal 2.000). That makes sense — at -110 / -110 the book is implicitly telling you the spread is a perfect 50/50. If your model says the Chiefs are 53% to cover, you have a 3% edge against the book's true probability estimate, which after a Kelly stake sizing becomes a real wager — not the 50.62% edge a naive read of the implied probability would suggest.
Why vig matters more than picks
Most bettors lose because they bet -EV markets at vig that's too high to overcome. A 55%-accurate cap on a -110 spread is +3% EV; the same cap at -120 is +0.4% EV; the same cap at -130 is negative. Shopping books for the lowest-vig price on the same line is the highest-leverage thing a serious bettor does — every point of vig you save is one point of edge you keep.
American / decimal / fractional / probability reference
| American | Decimal | Fractional | Implied prob |
|---|---|---|---|
| -400 | 1.250 | 1/4 | 80.00% |
| -300 | 1.333 | 1/3 | 75.00% |
| -250 | 1.400 | 2/5 | 71.43% |
| -200 | 1.500 | 1/2 | 66.67% |
| -180 | 1.556 | 5/9 | 64.29% |
| -150 | 1.667 | 2/3 | 60.00% |
| -130 | 1.769 | 10/13 | 56.52% |
| -120 | 1.833 | 5/6 | 54.55% |
| -110 | 1.909 | 10/11 | 52.38% |
| -105 | 1.952 | 20/21 | 51.22% |
| +100 | 2.000 | 1/1 | 50.00% |
| +105 | 2.050 | 21/20 | 48.78% |
| +110 | 2.100 | 11/10 | 47.62% |
| +120 | 2.200 | 6/5 | 45.45% |
| +130 | 2.300 | 13/10 | 43.48% |
| +150 | 2.500 | 3/2 | 40.00% |
| +180 | 2.800 | 9/5 | 35.71% |
| +200 | 3.000 | 2/1 | 33.33% |
| +250 | 3.500 | 5/2 | 28.57% |
| +300 | 4.000 | 3/1 | 25.00% |
| +400 | 5.000 | 4/1 | 20.00% |
FAQ
What is vig (vigorish) in sports betting? +
How do you remove the vig from American odds? +
Proportional vs. power devig — which method should I use? +
What is a "fair" odds price? +
Why does the no-vig calculator show different numbers than the book's "true odds"? +
Can I use this for parlays or correlated markets? +
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