Margin Calculator

Calculate the bookmaker's margin (vig) and find true odds using multiple devigging methods. See how much edge the book has built in.

Outcome 1
Outcome 2

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Example Markets

Devigging Methods Compared

Basic (Multiplicative)

Divides each probability by the total to normalize to 100%. Assumes margin is distributed equally.

Simple Less accurate

Shin Method

Recommended

Accounts for informed bettors. Assumes more margin on longshots, less on favorites. Industry standard.

Accurate Used by OddsElite

Power Method

Uses an exponent to adjust probabilities. Similar results to Shin but uses a different mathematical approach.

Accurate Alternative

Find odds with the lowest margin

OddsElite compares odds across bookmakers so you always bet at the best price. Lower margins mean higher expected value.

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Understanding Bookmaker Margin

What is Margin (Vig)?

The margin (also called vig, juice, or overround) is the bookmaker's built-in profit. It's the difference between the true probability of outcomes and the odds they offer. A 5% margin means for every $100 wagered, the bookmaker expects to keep $5 regardless of the outcome.

How Margin Works

For a fair coin flip (50/50), fair decimal odds would be 2.00 on both sides.

Fair Market (0% margin)

Both sides: 2.00

Total implied: 50% + 50% = 100%

With 4.5% margin

Both sides: 1.91 (-110)

Total implied: 52.4% + 52.4% = 104.5%

Why Devigging Matters

Devigging removes the bookmaker's margin to find the "true" probability and fair odds. This is essential for calculating expected value and identifying which side offers value. Sharp bettors always compare the devigged line (true odds) against their own probability estimate.

The Shin Method Explained

Developed by Hyun Song Shin, this method assumes bookmakers protect themselves against informed bettors by adding more margin to longshots. The intuition: insiders are more likely to bet on specific outcomes (longshots) where they have information. Shin's model is considered the most realistic representation of how bookmakers actually set odds.

Typical Bookmaker Margins

Bookmaker Type Typical Margin Example Odds Notes
Sharp Books (Pinnacle) 2-3% 1.95 / 1.95 Best prices, accept sharp action
Standard US Books 4-5% 1.91 / 1.91 (-110) Industry standard for spreads
Soft Books 6-8% 1.87 / 1.87 Higher margins, more promos
Soccer 3-Way 5-8% Varies 3 outcomes = higher margin
Props / Exotics 8-15% Varies widely Less liquid markets