Lay Bet Calculator
Lay stake, liability and a balanced exchange green book.
| Outcome | Net profit |
|---|---|
| Selection wins | −0.13 ₽ |
| Selection loses | −0.13 ₽ |
How it works
Laying a bet on an exchange means betting that a selection will NOT win — you take on the bookmaker's role. The lay stake is the amount the backer would win from you; your liability is lay stake × (lay odds − 1), the amount you risk if it does win.
To lock the same result whichever way it lands (the 'green book'), size the lay stake so the back bet's net profit equals the lay bet's. With equal back and lay odds the lay stake roughly matches the back stake; commission and a higher lay price shift it. This calculator solves for that balanced stake.
Lay Bet Calculator
Laying a bet on a betting exchange means backing a selection to lose — taking the bookmaker's side. This free lay calculator works out the lay stake and your liability, and solves for the balanced lay that locks in the same profit whichever way the event lands: the so-called green book.
Lay stake and liability
When you lay, the lay stake is the amount a backer would win from you, and your liability — what you actually risk — is lay stake × (lay odds − 1). Lay at 3.0 for a 10 stake and you risk 20 to win 10. Exchanges also take a commission, charged only on net winnings.
Laying is how you trade out of a back bet, cash out manually, or run a matched-betting position. The key number is the liability, because that is the money the exchange ring-fences from your balance.
Building a green book
A green book is a position where you profit the same amount no matter the result. To build it you size the lay stake so the back bet's net profit equals the lay bet's net profit. With identical back and lay odds and no commission, the lay stake equals the back stake; a higher lay price or commission nudges it.
The calculator solves lay stake = back × back odds ÷ (lay odds − commission), then shows the profit in each outcome so you can confirm the book is level before you place it.
What is a lay bet?expand_more
A bet that a selection will NOT win, placed on a betting exchange. You act as the bookmaker: you win the backer's stake if it loses and pay out if it wins.
What is liability in a lay bet?expand_more
The amount you risk if the lay loses (the selection wins). It equals lay stake × (lay odds − 1). Laying 10 at odds of 4.0 gives a liability of 30.
How do I lay to lock in a profit?expand_more
Size the lay stake so the back and lay net profits match: lay stake = back stake × back odds ÷ (lay odds − commission). That equalises the result either way — the green book.