Margin Sports Calculator
See the bookie's margin on a two-way market.
How to Use This Calculator
- Tap to choose your odds format (Decimal, Fractional, or American)
- Enter the odds for both outcomes
- If you like, add a stake to preview the payouts
- See the bookmaker margin along with the implied probabilities
Formula
Implied Probability = 1 / Decimal Odds
Bookmaker Margin (Overround) = (1 / Odds₁) + (1 / Odds₂) − 1
Payout = Stake × Decimal Odds
Margins below 5% are considered competitive; above 10% are typical of recreational books or low-liquidity markets.
Frequently Asked Questions
What does bookmaker margin actually mean?
Margin (also known as overround or vigorish) is how much the implied probabilities of every outcome add up to above 100%. It’s the bookmaker’s expected profit when their liability is balanced. A 5% margin means they expect to hold onto $5 of every $100 staked over time.
How is this different from the hold calculator?
They cover the same idea. This one is all about the practical side: drop in your stake and see what each outcome pays. The hold calculator leans more analytical and highlights fair (no-vig) odds so you can compare bookmakers.
Which bookmakers keep margins the lowest?
Sharp Asian books (Pinnacle, Sbobet) have historically run 2-3% margins on top markets. European recreational books usually sit around 5-8%. Promo or niche markets can climb past 15%.
Why does margin matter for long-term profit?
Margin is the headwind on every single bet. To break even at a 5% margin you have to win above the implied break-even rate. Lower-margin books simply make finding value bets easier.