Lay Bet Calculator
Exchange lay stake, liability and profit, matched precisely to a given back bet.
How to Use This Calculator
- Input the back stake amount
- Input the back odds from the bookmaker
- Input the lay odds from the betting exchange
- Input the exchange commission rate (default 5%)
- Read off the recommended lay stake, your liability, and the profit for each outcome
Formula
Lay Stake = (Back Stake × Back Odds) / (Lay Odds - Commission Rate)
Liability = Lay Stake × (Lay Odds - 1)
Profit if Back Wins = Back Stake × (Back Odds - 1) - Liability
Profit if Lay Wins = Lay Stake × (1 - Commission Rate) - Back Stake
Frequently Asked Questions
What is a lay bet?
A lay bet is the inverse of a standard (back) bet. When laying, you wager against an outcome occurring. If the selection loses, you collect the backer’s stake minus commission. If it wins, you pay out the winnings — your liability.
What does liability mean in lay betting?
Liability is the maximum loss exposure on a lay bet. It is computed as the lay stake multiplied by (lay odds - 1). The exchange holds this amount until the event settles.
Which exchange commission rate should I enter?
Betfair applies 5% standard commission on net winnings. Smarkets applies 2%. Certain exchanges grant reduced rates to high-volume users. Enter the rate that matches your specific exchange account.
Why do lay odds typically exceed back odds?
Lay odds run slightly higher because the exchange must match backers against layers. The spread between back and lay odds reflects the market’s efficiency. Tighter spreads indicate more liquid markets.