Why You Must Remove the Bookmaker Margin

Every set of odds you see on any Australian bookmaker has a built-in margin known as the vig, juice, or overround. This margin is how bookmakers guarantee profit regardless of the outcome. A fair market would have implied probabilities that sum to exactly 100%. In reality, Australian bookmakers typically operate at 104–108%.

How It Works

Enter the odds for each outcome. For football, include the draw odds for a 3-way market. The calculator shows the bookmaker's total overround and the true implied probability for each outcome with the margin stripped out.

Why This Matters for Finding Value

You cannot accurately assess whether odds offer value without first understanding what the bookmaker actually believes the true probability is. For example, odds of 1.90 on both sides of a market imply a 52.6% chance each — totalling 105.3%. Remove the vig and you find each outcome is roughly 50/50. A bookmaker operating at 102% gives you significantly better value than one at 108%.