Lay Bet Sports Calculator

Find the lay stake, liability and profit to match a back bet.

Please enter a valid stake amount
Please enter valid odds
Please enter valid odds
Results
Lay Stake --
Liability --
Profit if Back Wins --
Profit if Lay Wins --

How to Use This Calculator

  1. Type in the back stake amount
  2. Enter the back odds from the bookmaker
  3. Enter the lay odds from the betting exchange
  4. Add the exchange commission rate (default 5%)
  5. See the suggested 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's a lay bet?

A lay bet is the flip side of a regular (back) bet. When you lay, you’re betting against something happening. If the selection loses, you win the backer’s stake minus commission. If it wins, you cover the winnings (your liability).

What's liability in lay betting?

Liability is the most you could lose on a lay bet. It works out as the lay stake times (lay odds - 1). The exchange holds onto this amount until the event is settled.

What commission rate should I enter?

Betfair takes 5% standard commission on net winnings. Smarkets takes 2%. Some exchanges drop the rate for high-volume users. Just enter the rate that matches your exchange account.

Why are lay odds usually a bit higher than back odds?

Lay odds sit slightly higher because the exchange has to match backers with layers. That gap (the spread) between back and lay odds reflects how efficient the market is. Tighter spreads point to more liquid markets.