Lay betting explained: what a lay bet means in Australia
A lay bet is a bet that something will not happen. When you lay a horse, you win if it loses, and you pay out if it wins. You are acting as the bookmaker for someone else on a betting exchange.
That is the whole idea. The rest of this page is the detail: how liability works, where Australians can lay, what commission does to the numbers, and why laying is the half of matched betting most people have never heard of.
Back bet vs lay bet
Every bet you have placed at Sportsbet, TAB or Ladbrokes is a back bet: you back a selection to win. A lay is the other side of that same bet.
| Back bet | Lay bet | |
|---|---|---|
| You win if | The selection wins | The selection does not win |
| Most you can lose | Your stake | Your liability |
| Where | Any bookmaker or exchange | A betting exchange only |
| Commission | None at a bookmaker | On net market winnings |
Liability: the number that matters
When you lay, your stake is the amount the backer is risking, and the amount you could lose is bigger. That bigger number is your liability:
Liability = lay stake x (lay odds minus 1)
Lay a horse for $20 at odds of 4.00 and your liability is $20 x 3 = $60. If the horse loses, you win the $20, less commission. If it wins, you pay $60. Betfair holds the $60 from your balance until the race settles.
This is why lay odds matter so much. The same $20 lay at 11.00 carries a $200 liability. Long odds lays tie up a lot of money, which is the single biggest reason people run short of bank when they start.
Where you can lay bet in Australia
Bookmakers do not take lay bets. You need an exchange, where punters bet against each other and the exchange takes a commission instead of building a margin into the odds.
In Australia that means Betfair. It is the only betting exchange licensed to operate here, so when Australians talk about lay betting websites they mean Betfair. Commission is charged on your net winnings in each market: 8% on most Australian racing, 10% on NSW and ACT thoroughbreds, and 6% on most sport. The full breakdown, and how it changes your stakes, is on our Betfair commission by state page.
Why matched bettors lay
A lay on its own is just a bet with a big downside. The point is what happens when you pair it with a back bet on the same selection. Back a horse at a bookmaker, lay the same horse on Betfair, and one side wins whichever way the race goes.
Get the lay stake right and the two sides cancel out to a small, known amount, called the qualifying loss. You would never do that for its own sake. You do it because the back bet unlocks a bookmaker promotion, such as a bonus bet, a money back special or an early payout offer, and the promotion is where the value sits.
Worked example: back and lay on one horse
You back a horse for $50 at odds of 3.00 at a bookmaker. On Betfair the same horse can be laid at 3.10, with 8% commission (a VIC race).
| Lay stake | $50 x 3.00 / (3.10 minus 0.08) = $49.67 |
|---|---|
| Liability | $49.67 x 2.10 = $104.30 |
| Horse wins | Bookmaker +$100.00, Betfair minus $104.30 = minus $4.30 |
| Horse loses | Bookmaker minus $50.00, Betfair +$45.70 after commission = minus $4.30 |
Same result either way. That $4.30 is the cost of covering the bet. The calculator does this sum for you, including commission: use the matched betting calculator rather than doing it by hand on race day.
Mistakes that cost money
- Backing on the exchange by accident. Betfair shows blue back prices and pink lay prices side by side. Click the wrong colour and you are doubled up, not covered.
- Ignoring liability. Check you can fund the liability before you place the bookmaker bet, not after.
- Leaving the lay unmatched. A lay you requested is not a lay you have until it shows as matched. Unmatched bets can lapse at the jump.
- Using the wrong commission. A NSW thoroughbred race is 10%, not 8%, and the lay stake should reflect that.
Where to go next
Laying is one skill inside a bigger process, set out on our matched betting in Australia guide. The bonus bets by bookmaker hub covers what each operator offers, all of our tools sit on the calculators page, and the common questions are on the FAQ. If you want to see the process done with real offers, the free five episode bootcamp walks through it, and there is a 7 day free trial if you want to try it with the community. You must be 18 or over.
Frequently asked questions
What does lay mean in betting?
To lay a selection is to bet that it will not win. You take the bookmaker's role: if the selection loses, you keep the backer's stake; if it wins, you pay the backer's winnings. The amount you could have to pay is called your liability.
Is lay betting legal in Australia?
Yes. Betfair operates a licensed betting exchange in Australia under a Northern Territory licence, and laying on it is permitted for adults. Ordinary bookmakers such as Sportsbet or TAB do not let you lay; only an exchange does.
What are the lay betting websites in Australia?
Betfair is the only betting exchange licensed to operate in Australia, so it is where Australians lay bets. Overseas exchanges are not licensed here and should not be used.
What is liability in a lay bet?
Liability is the most you can lose on a lay: the lay stake multiplied by the lay odds minus one. A $20 lay at odds of 4.00 has a liability of $60. Betfair holds that amount from your balance until the market settles.
Do I pay commission on a lay bet?
Only when you win. Betfair charges commission on your net winnings in each market, so a lay that wins pays commission and a lay that loses does not. Most Australian racing is charged at 8%, NSW and ACT thoroughbreds at 10%.
Why do matched bettors lay bets?
To cover a bookmaker bet. Backing a selection at a bookmaker and laying the same selection on Betfair means one side wins whichever way the result goes, which turns a bookmaker promotion into a fixed, known amount instead of a gamble on the result.
Is laying the favourite a strategy?
On its own, no. A lay with nothing on the other side is a normal bet with a large liability. Matched bettors only lay to cover a back bet they have already placed, so the result stops mattering.
Written by the YAUPICKS team. Last reviewed 18 October 2026.
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