Betfair Lay Liability Calculator — Free Back/Lay Tool

How to Use This Calculator

This tool shows your potential profit or loss from a bet on a betting exchange (like Betfair or Smarkets).

Trade Type:
- Back: A normal bet *for* something to win.
- Lay: A bet *against* something to win.
Stake:
- For a Back Bet, this is the amount you risk.
- For a Lay Bet, this is the *backer's stake* (the amount you want to win).
Commission Rate: Your exchange's fee on net winnings (e.g., enter `5` for 5%).

Understanding the Terms

Example Back Bet: You back £10 at 3.0 odds.

Win: You profit £20 (minus commission).
Lose: You lose your £10 stake.

Example Lay Bet: You lay £10 at 3.0 odds.

Win (Selection Loses): You profit £10 (minus commission).
Lose (Selection Wins): You lose £20. This is your liability.

Determine profit and liability for simple Back or Lay bets.

Odds (Decimal): Stake (£): Trade Type: Exchange Commission Rate (%):

Results:

When to use this calculator

Use this calculator before placing any lay bet on Betfair. It shows your maximum liability (what you lose if the selection wins) and your profit if it loses. Switch between back and lay to compare both sides of the trade.

Essential for Lay the Draw, laying favourites, and any strategy where you need to know your exact exposure before clicking submit.

Frequently asked questions

What is lay liability on Betfair?

Liability is the amount you lose if the selection you laid wins. It equals your lay stake multiplied by (lay odds − 1).

What stake should I enter for a lay bet?

Enter the backer’s stake — the amount you stand to win if the selection loses, not your liability.

Does this include Betfair commission?

Yes. Enter your commission rate (default 5%) and the calculator deducts it from winning outcomes.

Disclaimer: For educational and planning purposes only. Not financial or betting advice. 18+ · BeGambleAware.org