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Frequently Asked Questions
What is a lay bet?
A lay bet is a bet against a selection winning. When you lay on a betting exchange such as Betfair or Smarkets, you act as the bookmaker. If the selection loses, you keep the backer's stake (minus commission). If the selection wins, you pay out their winnings — this potential payout is called your liability.
How is lay bet liability calculated?
Liability = Lay Stake × (Lay Odds − 1). For example, laying £10 at odds of 4.0 gives a liability of £10 × (4.0 − 1) = £30. This is the maximum amount you could lose if the selection wins.
What is exchange commission and how does it affect profit?
Exchanges charge a commission on net winnings, typically 2–5%. Your net profit when your lay wins = Lay Stake × (1 − Commission Rate). On a £10 lay at 2% commission, profit = £10 × 0.98 = £9.80. Commission is only charged on winning markets.
What is the implied win probability from lay odds?
The implied probability of the selection winning = 1 ÷ Lay Odds × 100. At lay odds of 4.0, the market implies a 25% chance of winning. If you believe the true probability is lower than this implied figure, you have a positive edge laying that selection.
What is a good lay bet strategy?
Successful lay betting requires identifying overpriced favourites where the market's implied probability exceeds the true probability. Strategies include laying odds-on favourites in large fields, trading out positions before an event ends, and using lay betting as part of matched betting to cover free bet offers.