Margin / Vig Calculator
Calculate the bookmaker's margin (vigorish) on a two-way market. Lower margins mean better value for bettors.
Bookmaker Margin
4.71%
Overround
1.0471
Payout Rate
95.50%
Implied Prob 1
52.36%
Implied Prob 2
52.36%
True Prob 1
50.00%
True Prob 2
50.00%
Three-Way Market (e.g. Soccer)
3-Way Margin
4.79%
3-Way Overround
1.0479
3-Way Payout
95.43%
Understanding Bookmaker Margins
The margin (also called vig, vigorish, or juice) is the bookmaker's built-in edge. It's the percentage above 100% when you sum the implied probabilities of all outcomes.
Typical margins: Mid-range: 4-6%
True probability removes the margin to show the bookmaker's actual assessment of each outcome's likelihood. Use this to find value bets where your estimated probability exceeds the true probability.
Frequently Asked Questions
What is the bookmaker margin (vig)?
The margin, also called vig or juice, is the built-in edge a book charges: the amount by which the combined implied probabilities of all outcomes exceed 100%.
How is betting margin calculated?
Sum the implied probabilities (1 divided by decimal odds) of every outcome. A two-way market priced 1.91 / 1.91 sums to about 104.7%, so the margin is roughly 4.7%.
Why does margin matter?
The lower the margin, the better the odds and the more you keep long term. Comparing margins across books shows which offers the sharpest, most valuable prices.
What is a fair (no-vig) price?
Removing the margin proportionally gives the true implied probability for each outcome, which is useful for estimating fair value and finding positive-EV bets.
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