How to Use the Vig Calculator
The Betstamp Vig Calculator shows you how much margin (also known as juice or overround) a sportsbook has built into a betting market. This “vig” is how sportsbooks make their money — and knowing the vig helps you evaluate whether a line is sharp, soft, or worth avoiding.
Quick Start:
- Choose your preferred odds format: American, Decimal, or Fractional.
- Enter the odds for both sides of the market.
- The calculator instantly displays the bookmaker’s vig percentage — the total margin they’ve added on top of true probability.
Example:
Say a book lists:
- Team A: -115
- Team B: -105
Input those odds into the calculator.
It returns a vig of 3.2%, meaning the combined implied probabilities of both lines add up to 103.2%. That extra 3.2% is the sportsbook’s built-in profit margin.
A few rules of thumb:
- 0% vig = true fair market (rare)
- <2% vig = sharp or efficient market
- >4% vig = inflated margin, often found on smaller markets or props
This tool is essential when comparing lines across books or looking to bet into low-hold markets where your edge isn’t immediately eroded by juice.
With Betstamp PRO—the most advanced top-down betting odds screen in the market. Bettors will find hundreds of daily betting edges with ease, allowing you to scale your profits long-term. Click the banner to book a free demo.
