Bookmaker Margin Calculator
Calculate the bookmaker's margin (overround/vig) to understand how much they take from every market.
Enter Market Odds
Understanding Bookmaker Margin
The margin (also called overround, vig, or juice) is how bookmakers guarantee profit. In a fair market, implied probabilities sum to 100%. Bookmakers inflate this to 102-110%, keeping the difference.
Example
A coin flip should be 2.00 for both sides (50% + 50% = 100%). Bookmakers might offer 1.91 each, giving: 52.4% + 52.4% = 104.8%. The 4.8% is their margin.
Why It Matters
Lower margin = better odds = better value for you. A 2% margin bookmaker gives you significantly better long-term returns than a 6% margin bookmaker.
Typical Margins
Pinnacle: 2-3% (best odds)
Bet365, Unibet: 4-6%
High street bookies: 6-10%
Novelty markets: 10-20%+