Vig and Margin Calculator
Enter decimal odds for a 2-way or 3-way market to reveal the bookmaker's hidden margin, expected payout, and the fair no-vig probabilities behind the board.
Calculate Bookmaker Margin
Formula
Vig = ((1 / odds1) + (1 / odds2) + (1 / odds3) - 1) * 100
How to Read the Output
Bookmaker Margin
The vig is the amount by which the summed implied probabilities exceed 100%. In a two-way market priced at 1.91 and 1.91, the total implied probability is 104.71%, which means the book is holding 4.71% margin.
Expected Payout
Payout is just the inverse of the summed implied probability. It tells you how much of a perfectly fair 100% market remains after the bookmaker takes its cut.
Fair No-Vig Probabilities
These normalize the market back down to 100%. Once you remove the vig, you get cleaner probabilities and fairer odds to use when comparing prices across books or building your own model.
Related Tools and Guides
Risk Control Reminder
Removing the vig does not automatically create a bet. It only gives you a cleaner baseline. You still need your own model, your own fair probability estimate, and disciplined bankroll sizing before any wager deserves real money.