Betting Markets
Understanding Vig
What the vig (juice) is, how to measure a sportsbook's margin, and how to remove it to find a fair price.
By Jared Narz · · 2 min read
The vig (short for vigorish, also called juice) is the margin a sportsbook builds into its prices. It's how books make money regardless of who wins.
The classic example
On a standard spread, both sides are priced at -110. If one bettor puts $110 on each side, the book collects $220 and pays $210 to the winner. That $10 is the margin.
Measuring the vig
Convert both sides to implied probability and add them up:
- -110 / -110: 52.38% + 52.38% = 104.76%
- -105 / -105: 51.22% + 51.22% = 102.44%
The amount over 100% is the overround. The book's theoretical hold is 1 − 1 / total:
- -110 / -110 → about 4.5%
- -105 / -105 → about 2.4%
Lower is better for you.
Removing the vig (no-vig fair odds)
To estimate the market's fair probability, divide each side's implied probability by the total.
Illustrative: Side A -150 (60.0%), Side B +130 (43.5%). Total = 103.5%.
- Fair A ≈ 60.0 / 103.5 = 58.0%
- Fair B ≈ 43.5 / 103.5 = 42.0%
Why it matters
- The vig is a cost on every bet. Over hundreds of bets, it adds up.
- Props, futures and parlays often carry much more vig than main markets.
- Reduced-juice books, exchanges and prediction markets can offer lower margins.
- No-vig prices from sharp markets are the starting point for estimating expected value.
Examples are illustrative and use hypothetical numbers. This article is educational content, not financial advice or a guarantee of results. 21+. Bet responsibly.