Lay Betting Tool
Determine the exchange lay stake, liability and profit matched to a back bet.
How to Use This Calculator
- Enter the amount of your back stake
- Enter the back odds from the bookmaker
- Enter the lay odds from the betting exchange
- Enter the exchange commission rate (the default is 5%)
- Review 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 mirror image of an ordinary back bet. By laying, you are wagering against an outcome occurring. Should the selection lose, you collect the backer’s stake less commission. Should it win, you must settle the winnings — this is your liability.
What does liability mean in lay betting?
Liability is the largest amount you stand to lose on a lay bet. It is calculated as the lay stake multiplied by (lay odds - 1). The exchange holds this sum until the event has been settled.
Which exchange commission rate should I enter?
Betfair applies a standard 5% commission on net winnings, while Smarkets charges 2%. Certain exchanges grant reduced rates to high-volume customers. Enter whichever rate corresponds to your particular exchange account.
Why do lay odds tend to exceed back odds?
Lay odds sit marginally higher because the exchange must pair backers with layers. The gap, or spread, between back and lay odds reflects the efficiency of the market. The tighter the spread, the more liquid the market.