What Is a Lay Bet?
A lay bet is a bet that a specific outcome will NOT happen. When you lay a selection on Betfair Exchange, you are taking the other side of someone else's back bet — you become the bookmaker for that transaction.
If the selection you've laid does NOT win, you collect the backer's stake as your profit. If the selection DOES win, you pay out their winnings. This payout amount is your liability — the maximum you can lose on a lay bet.
You lay Tottenham at 4.00. A backer has staked £50 on them.
If Tottenham do NOT win (your prediction is correct): You collect the backer's £50 stake. Profit = £50 (minus commission).
If Tottenham WIN (you're wrong): You pay out (4.00 − 1) × £50 = £150 to the backer.
Your maximum loss: £150. Betfair holds this in your account before the bet goes live.
One lay bet can't cover just one backer — Betfair may split your lay stake across multiple backers at the same price. But from your perspective, the maths is identical regardless of how many backers are matched against you.
How Liability Works — Critical
Liability is the single most important concept to understand before placing any lay bet. Many beginners grasp lay betting intellectually but get badly burned by not understanding what they're actually risking.
Liability formula: (Odds − 1) × Backer's Stake = Your Maximum Loss
The backer's stake in the liability formula is the total amount matched against you — not what you enter as your "stake" in the bet slip. On Betfair's bet slip, when you lay a bet, you enter the backer's stake amount. The interface then shows you both the potential profit (what you collect if you win) and the liability (what you pay if you lose).
Example 1: Short-priced lay
Lay Man City at 1.50, backer's stake £100.
Liability = (1.50 − 1) × £100 = £50. Profit if correct = £100.
Example 2: Medium-priced lay
Lay a horse at 5.00, backer's stake £50.
Liability = (5.00 − 1) × £50 = £200. Profit if correct = £50.
Example 3: High-odds lay
Lay an outsider at 25.00, backer's stake £10.
Liability = (25.00 − 1) × £10 = £240. Profit if correct = £10.
Notice: as odds increase, the risk/reward ratio becomes increasingly unfavourable for the layer. Laying high-odds outsiders is not inherently low-risk — your liability is significant relative to potential profit.
Liability at Different Odds
Betfair reserves the full liability in your account before a lay bet is placed. If you don't have sufficient funds, the bet will not go through.
| Odds | Backer's Stake | Your Profit if Correct | Your Liability (max loss) |
|---|---|---|---|
| 1.30 | £100 | £100 | £30 |
| 2.00 | £100 | £100 | £100 |
| 3.00 | £100 | £100 | £200 |
| 5.00 | £100 | £100 | £400 |
| 10.00 | £100 | £100 | £900 |
| 20.00 | £100 | £100 | £1,900 |
| 50.00 | £100 | £100 | £4,900 |
The table makes something important very clear: lay bets on high-odds selections have enormous liabilities relative to potential profit. Laying a 50/1 shot for £100 backer's stake means risking £4,900 to win £100. Even with a 90%+ strike rate, one winner at long odds can wipe months of accumulated lay profits.
Professional layers focus on short-to-medium priced selections (odds of 1.10–8.00) where the liability is manageable relative to the potential profit. See Laying Horses on Betfair for the specific strategies used in horse racing.
Betfair reserves the full liability amount before a lay bet goes live. If your available balance is less than the required liability, Betfair will not place the bet. This is a feature, not a bug — it prevents you from placing bets you can't cover. Never deposit extra funds mid-session under pressure to cover a position. If your balance is insufficient, reduce your stake.
How to Place a Lay Bet
On the standard Betfair website, lay bets are placed from the pink/red column in the market view:
- Navigate to the market and find your selection in the Exchange view (not Sportsbook).
- Click the pink lay price next to the selection you want to lay. The pink column shows current lay prices — the best price available for you as a layer.
- The bet slip opens showing the lay price and two input fields: backer's stake (what you'll collect if correct) and liability (shown automatically).
- Enter the backer's stake amount — for example, £50. The bet slip will show your liability automatically.
- Check the liability figure carefully before confirming. Make sure it's within your budget.
- Click Place Bet and confirm. Your lay bet is placed and the liability is reserved from your balance.
You lay the draw in Arsenal v Chelsea at 3.50.
You enter backer's stake: £40.
Bet slip shows: Profit if no draw = £40. Liability = (3.50 − 1) × £40 = £100.
Betfair reserves £100 from your balance immediately. You need at least £100 available.
If the game is not a draw: you collect £40 (minus commission). Liability released.
If the game is a draw: you pay £100. Your stake of £40 profit is irrelevant — you're paying the payout from the reserved liability.
Commission on Lay Bets
Commission on lay bets works the same way as on back bets — it's charged on your net winnings in the market, not on your stake or liability. If you lay and win, commission is deducted from your profit. If you lay and lose, no commission is charged.
Lay a horse at 3.00. Backer's stake £60. Horse loses. You collect £60.
Horse racing market at 2% commission: £60 × 2% = £1.20.
Net profit: £58.80.
If trading in a football market at 5%: commission = £3.00. Net profit = £57.00.
When Does Laying Make Sense?
Lay betting makes sense in several specific scenarios:
- Closing a trading position: You backed a selection earlier and the odds have moved in your favour. Laying now at a lower price locks in profit (or reduces loss) regardless of the result. This is the core of back-to-lay trading.
- Opening a lay-to-back position: You believe a selection's price will drift (move longer). You lay now at the current price and back later at a longer price, profiting from the move. See swing trading.
- Matched betting: Using a bookmaker free bet combined with an Exchange lay to extract near-guaranteed value from promotional offers. See matched betting guide.
- Football Lay the Draw: Lay the draw before kick-off and trade out when a goal is scored (the draw price lengthens dramatically after a goal). See Lay the Draw strategy.
- Laying a false favourite: When the market has overestimated a selection's probability and the lay price underestimates your true assessment of the chance it won't win. Requires genuine edge — not just opinion.
Lay-to-Back Trading
Laying first then backing later is the mirror image of back-to-lay trading. Instead of buying low and selling high, you're selling high and buying back low — exactly like short-selling in financial markets.
Situation: Pre-race, your analysis suggests the market favourite is too short. The current price is 2.00 and you expect it to drift to 2.40+ before the off.
Open position: Lay favourite at 2.00. Backer's stake £100. Your liability = (2.00 − 1) × £100 = £100. Potential profit if correct = £100.
30 minutes later: Price drifts to 2.40 (market has backed away from the favourite — perhaps the trainer's comments were cautious).
Close position: Back the same horse at 2.40 with a calculated stake of £83.33.
Result if horse wins: Back pays (2.40 − 1) × £83.33 = £116.66. Lay costs £100. Net = +£16.66.
Result if horse loses: Back loses £83.33. Lay collects £100. Net = +£16.66.
Guaranteed ~£16.66 profit regardless of result (before commission).
Use our trading calculator to find the correct back stake for any lay-to-back position. The maths is identical to back-to-lay, just reversed.
Lay Bets in Matched Betting
Matched betting uses bookmaker free bets combined with Exchange lay bets to produce near-guaranteed profit. The principle: back a selection at the bookmaker using a free bet, lay the same selection on the Exchange. One side wins, one loses — but because the back side uses a free bet (no stake risk), the net result is almost always positive.
This is not the same as trading — it's specifically exploiting promotional offers. Once all offers from a bookmaker have been used, the matched betting opportunity ends. See our full matched betting guide for a complete walkthrough. The Exchange's lay facility is what makes matched betting possible — no traditional bookmaker allows it.
Common Mistakes with Lay Betting
- Confusing backer's stake with your own stake: When you enter £50 as backer's stake, you're not risking £50 — you're potentially paying out the liability. The two numbers are completely different. Always check the liability figure before confirming.
- Laying high-odds selections without understanding the liability: Laying a 20.00 shot for £50 backer's stake means risking £950. Many beginners don't calculate this properly and are shocked when a longshot wins.
- Not having enough balance for the liability: Betfair won't let the bet go through — but beginners sometimes try to add funds mid-session to cover a position they've already emotionally committed to. This is a bad habit. Know your liability before you place the bet.
- Opening lay positions without an exit plan: If the price moves against you (the selection shortens), your lay position is losing. Know in advance at what price you'll close the trade at a small loss rather than holding and hoping.
- Confusing a lay with a guaranteed win: Favourites do win. Short-priced selections win more often than not. A lay bet at 1.30 means you're risking £30 to win £100 — but that selection will win roughly 75% of the time if the market is accurate. Only lay when you have a specific reason to believe the market has overestimated the probability.
Lay betting can result in losses significantly larger than your initial stake if you lay at long odds. Always calculate the full liability before placing any lay bet. Never lay a position you cannot afford to have go wrong. Use the bankroll management rules to size all lay bets appropriately. Visit Responsible Gambling if you have concerns about your gambling.
Ready to practice? Use our calculator to understand lay liability before placing real bets. Then read the green-up guide to learn how to close lay positions cleanly.
Trading Calculator Green Up Guide