Betting Calculators
Lay Bet Calculator
Calculate lay bet stakes, liability, and profit for betting exchange wagers. Find the optimal lay stake to match your back bet and see potential outcomes.
How to Use This Calculator
- Enter the back stake amount
- Enter the back odds from the bookmaker
- Enter the lay odds from the betting exchange
- Enter the exchange commission rate (default 5%)
- View the recommended lay stake, your liability, and 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 opposite of a normal (back) bet. When you lay, you are betting against an outcome happening. If the selection loses, you win the backer’s stake minus commission. If it wins, you pay out the winnings (your liability).
What is liability in lay betting?
Liability is the maximum amount you could lose on a lay bet. It equals the lay stake multiplied by (lay odds - 1). This amount is held by the exchange until the event is settled.
What exchange commission should I use?
Betfair charges 5% standard commission on net winnings. Smarkets charges 2%. Some exchanges offer reduced rates for high-volume users. Enter the rate for your specific exchange account.
Why are lay odds usually higher than back odds?
Lay odds are slightly higher because the exchange needs to match backers with layers. The difference (spread) between back and lay odds represents the exchange’s market efficiency. Tighter spreads mean more liquid markets.