Bookmaker margin calculator
Calculate overround and find sharp lines
Calculate a bookmaker's overround (margin, vig, juice) — the lower the number, the better the odds.
What is bookmaker margin?
Margin is the bookmaker's built-in profit on a market. If the true probabilities of all outcomes in an event sum to exactly 100%, the bookmaker prices them slightly lower so they add up to 105% or 108% — that extra is their guaranteed take. The lower the margin, the better the odds you get.
Pinnacle famously runs at 2-3% margin on major sports. Most retail bookmakers run 5-8%. Some run 12%+ on niche markets. Over hundreds of bets, this difference is the gap between profit and slow bankruptcy. Once you've found a sharp bookmaker, use our No-vig calculator to extract their fair odds and Value Bet finder to identify mispriced soft-book offers.
See also: Odds converter, Arbitrage calculator, No-vig (fair odds)
How to use this calculator
- 1Enter the decimal odds of each outcome in a market (2-way for tennis, 3-way for football with the draw).
- 2The calculator sums the implied probabilities and shows the margin as a percentage.
Example: comparing two football odds
Bookmaker A offers 2.10 / 3.50 / 3.60 on Home/Draw/Away. Implied probs: 47.6% + 28.6% + 27.8% = 104.0% — a 4% margin. Bookmaker B offers 2.00 / 3.40 / 3.50 on the same match. Implied: 50.0% + 29.4% + 28.6% = 108.0% — an 8% margin. Bookmaker A is twice as sharp. Over 100 bets, you'd expect to be roughly 4% better off using A.
When to check margin
- Before opening an account — pick low-margin bookmakers
- When deciding where to place a specific bet — same line, lower margin always wins
- To spot overpriced markets and avoid them
Frequently asked questions
What is the Bookmaker margin calculator calculator?
Margin is the bookmaker's built-in profit on a market. If the true probabilities of all outcomes in an event sum to exactly 100%, the bookmaker prices them slightly lower so they add up to 105% or 108% — that extra is their guaranteed take.
How does the Bookmaker margin calculator calculator work in practice?
Bookmaker A offers 2.10 / 3.50 / 3.60 on Home/Draw/Away. Implied probs: 47.6% + 28.6% + 27.8% = 104.0% — a 4% margin. Bookmaker B offers 2.00 / 3.40 / 3.50 on the same match. Implied: 50.0% + 29.4% + 28.6% = 108.0% — an 8% margin. Bookmaker A is twice as sharp. Over 100 bets, you'd expect to be roughly 4% better off…
When should I use the Bookmaker margin calculator calculator?
Before opening an account — pick low-margin bookmakers. When deciding where to place a specific bet — same line, lower margin always wins. To spot overpriced markets and avoid them.