Vig / vigorish
Updated November 10, 2026
Vig (vigorish) is the margin a sportsbook builds into its odds so implied probabilities sum to more than 100%. The excess, often called overround, is the book’s edge before an outcome is known.
Team A −110 and Team B −110 both imply about 52.4% each, 104.8% total. The 4.8% overround is the vig. A sportsbook customer on −110/−110 lines needs to win more than half the time just to break even after that margin. Prediction markets on $1 binaries do not use this two-sided book structure; see no-vig / fair odds for the contrast.
- Implied by −110, each side
- 52.4%
- Both sides together
- 104.8%
- Overround: the book's margin
- 4.8%
Vig is why sportsbook “implied probabilities” must be normalized before you compare them to your own forecast or to a prediction market price.
On a liquid $1 binary, yes and no prices often sum near 100% without that step; the price reflects traders’ beliefs, not a bookmaker’s built-in margin.
How to calculate vig from American odds
Convert each side to an implied probability, add them up, and subtract 100%.
- Negative odds (−X): implied probability = X ÷ (X + 100). At −110, that is 110 ÷ 210 = 52.38%.
- Positive odds (+X): implied probability = 100 ÷ (X + 100). At +130, that is 100 ÷ 230 = 43.48%.
The −110/−110 line is symmetric, so the margin splits evenly. Many lines aren't. A two-way line at −150 / +130 implies 60.0% and 43.5%, for a total of 103.5%, an overround of 3.5%. Removing it is what no-vig / fair odds does, and the no-vig probability calculator runs the arithmetic for two-way and three-way lines.
Overround and hold
Two figures go by "vig," and they measure the margin differently.
Overround is the excess over 100% in the implied probabilities: 4.76% on −110/−110, shown above rounded to 4.8%.
Hold is the share of the money taken in that the book keeps if it has balanced action on both sides. At −110/−110, a customer risks $110 to win $100. With $110 on each side, the book takes in $220, pays the winner $210 (the $110 stake back plus $100), and keeps $10. That is 10 ÷ 220, or about 4.55%.
- Overround
- 4.76%
- 104.76% total implied, minus 100%
- Hold on balanced action
- 4.55%
- $10 kept of $220 taken in
The two always move together: hold equals overround divided by the total implied probability (4.76 ÷ 104.76). When you compare margins across books or lines, compare the same measure.
FAQ
How do you calculate vig?
Convert each side's odds to an implied probability, add them, and subtract 100%. At −110/−110 that is 52.38% + 52.38% − 100% = 4.76%.
Is vig the same as juice?
Yes. Vig, vigorish and juice are all names for the margin a sportsbook builds into its odds.
Do prediction markets have vig?
A prediction market price has no bookmaker's margin built into it, because traders set it by trading with each other. The trading costs you see instead are the spread and explicit fees. On Lumina, that is a $0.01 per-contract exchange fee per side plus a 0.35% commission on trade value.