A lay betting strategy is a price rule plus a liability cap: lay only below a runner's fair price by more than the commission, and limit what each lay and each day can lose. It is the value logic of backing turned around, and the same sums show when a back is the better bet.
Every price below is hypothetical, chosen to show the arithmetic, and none of it is a lay tip. A lay at a good price still loses whenever the runner wins.
Laying is backing in reverse
Laying a runner is betting that it will not win. You accept a backer's bet at their price, so a lay at $4.00 sells the runner's chance at 1 / 4.00 = 25%. If the real chance is lower, the lay has the edge; if it is higher, the backer does.
| Back bet | Lay bet | |
|---|---|---|
| Has value when the price is | longer than fair | shorter than fair |
| Wins if right | stake x (odds - 1) | the backer's stake |
| Pays if wrong | the stake | lay stake x (odds - 1) |
| Pays commission on | a winning back | a winning lay |
The difference is the shape of the payoff. A back at $4.00 risks $1 to win $3, and a lay at $4.00 risks $3 to win $1, so lays win more often and lose bigger. How to lay a bet covers placing one, liability covers the formula, and the lay betting hub covers the rest of the exchange side.
Lay methods that depend on betting during a match, such as laying the draw in soccer, cannot be used online in Australia: under the Interactive Gambling Act 2001, an online bet on a sporting event has to be placed and accepted before it begins (s 10B and s 8A(3)).
The fair price and the commission hurdle
A strategy needs a fair price to lay against: your own ratings, a bookmaker market with its margin taken out, or the exchange midpoint. Each is an estimate that has to earn trust on your own records, and exchange price as fair odds sets out the midpoint method and where it fails.
Commission sets the hurdle. It is charged only when a lay wins, so the highest price you can lay at and still break even is:
break-even lay price = 1 + (fair price - 1) x (1 - commission rate)
At an illustrative 8% rate, a fair $4.00 runner breaks even as a lay at 1 + 3 x 0.92 = $3.76. A back needs the mirror image: a fair $6.00 runner has to be backed at 1 + (fair price - 1) / (1 - commission rate) = 1 + 5 / 0.92 = $6.43 or longer.
| Fair price | Back needs at least (8%) | Lay needs at most (8%) |
|---|---|---|
| $1.50 | $1.54 | $1.46 |
| $2.00 | $2.09 | $1.92 |
| $3.00 | $3.17 | $2.84 |
| $4.00 | $4.26 | $3.76 |
| $6.00 | $6.43 | $5.60 |
| $10.00 | $10.78 | $9.28 |
Between the two columns sits a band where neither side pays. A lay at $3.80 on a fair $4.00 runner looks shorter than fair, yet it is worth 0.75 x 0.92 - 0.25 x 2.80 = 0.69 - 0.70 = -1 cent per dollar of lay stake.
If your fair price is the exchange's own midpoint, the best lay price sits above it by half the spread, so a lay at the market price starts behind before commission is counted. A value lay needs a fair price that disagrees with the exchange, and evidence that the disagreement is right.
Risk: Betting involves risk. Your fair price is only an estimate: a lay that clears the hurdle on paper can still be a losing bet, and the runner can win however good your price was. See responsible gambling for limits and support.
Short favourites vs mid-priced runners
Laying short favourites and laying mid-priced runners look like two strategies, but one piece of maths runs both. What changes is how often the lay wins, how much one loser costs, and how hard commission bites.
With hypothetical prices, here are two lays whose implied chances each sit about 2 percentage points above the fair chance. Both use an illustrative 8% commission and carry $100 of liability:
| Short favourite | Mid-priced runner | |
|---|---|---|
| Fair price (chance) | $2.00 (50.0%) | $8.00 (12.5%) |
| Lay price (implied chance) | $1.92 (52.1%) | $6.90 (14.5%) |
| Lay stake for $100 liability | 100 / 0.92 = $108.70 | 100 / 5.90 = $16.95 |
| Kept if the runner loses, after 8% | $100.00 | $15.59 |
| Paid if the runner wins | $100.00 | $100.00 |
| How often the lay wins | 50.0% | 87.5% |
| Expected result before commission | +$4.35 | +$2.33 |
| Expected result after commission | $0.00 | +$1.14 |
Kept = lay stake x 0.92: 108.70 x 0.92 = $100.00 and 16.95 x 0.92 = $15.59. Before commission, a lay is worth its win chance x lay stake - the runner's win chance x liability: 0.5 x 108.70 - 0.5 x 100 = +$4.35, and 0.875 x 16.95 - 0.125 x 100 = 14.83 - 12.50 = +$2.33.
Before commission the favourite lay looks better. After it, the favourite lay is worth nothing, because each winning lay pays 8% on a $108.70 stake: 0.5 x 108.70 x 0.08 = $4.35 a lay on average, the whole edge. The mid-priced lay pays commission on $16.95 and keeps about half its edge: 2.33 - 0.875 x 16.95 x 0.08 = 2.33 - 1.19 = $1.14.
The mid-priced lay pays for that in swings. It wins 87.5% of the time, but one loser costs as much as 100 / 15.59 = 6.4 winners. The decision rule:
- Lay a short favourite only when the gap to fair is wide enough to clear commission on a stake bigger than the liability.
- Lay a mid-priced runner only under a liability cap that survives a run of losers.
Risk: Betting involves risk. Both expected results are averages over many lays at prices you would have to find again and again, and the $6.90 lay loses its full $100 every time that runner wins. See responsible gambling for limits and support.
Liability caps per lay and per day
Cap liability, not stake. A fixed lay stake lets the worst case grow with the price: $10 at $1.60 risks $6, $10 at $4.00 risks $30 and $10 at $12.00 risks $110. A fixed liability keeps the worst case the same at every price.
With an illustrative $2,000 bank, a cap of 2% ($40) per lay and 8% commission:
| Lay price | Lay stake, 40 / (price - 1) | Kept if the runner loses, stake x 0.92 |
|---|---|---|
| $1.60 | $66.67 | $61.33 |
| $2.50 | $26.67 | $24.53 |
| $4.00 | $13.33 | $12.27 |
| $7.00 | $6.67 | $6.13 |
| $12.00 | $3.64 | $3.35 |
The lay bet calculator works out the lay stake for any cap and price, at your own commission rate.
The cap shows what laying long prices costs: at $12.00 you risk $40 to keep $3.35. If you lay two runners in one race, the cap applies to the race's worst case, not to each lay.
A daily cap limits what one bad afternoon can do to the bank. Two that work together, on the same illustrative bank:
- Total open liability: no more than $160, four full lays, matched and unsettled at once.
- Daily loss stop: once the day's settled lays are down $120, stop laying until tomorrow.
Set both before the day starts and never lift them to win back a loss. The firmer cap sits with the exchange. Under the National Consumer Protection Framework, Australian online wagering providers must offer a deposit limit, and a lower limit applies at once while a higher one waits 7 days.
Risk: Betting involves risk. A cap limits losses only while you keep to it, and a lay that is already matched pays its full liability whatever your plan said. See responsible gambling for limits and support.
When laying beats backing
Laying is the better tool when your view is against one runner rather than for another. Say you think a favourite is too short in a hypothetical race. Laying it at $2.50 is the same position as backing every other runner together at 1 + 1 / 1.50 = $1.67, or about $1.61 after an illustrative 8% commission (1 + 0.667 x 0.92 = 1.61).
To build that position at a bookmaker, you would back each of the other runners in proportion, and the combined price is 1 / (the sum of their implied chances). If their implied chances add up to 72.5% (illustrative), the combined bet pays 1 / 0.725 = $1.38. The lay avoids the bookmaker's margin on every one of those runners.
Back instead when:
- you like one runner rather than dislike another, and its price clears the back column of the hurdle table;
- the only lays on offer are long, where a capped liability buys a small win;
- the exchange market is thin and the lay price sits well above the midpoint.
Risk: Betting involves risk. A lay swaps the bookmaker's margin for commission, not for certainty: if the runner you laid wins, the full liability goes, and there is no guarantee of profit. See responsible gambling for limits and support.
Laying horses: what changes the maths
Racing adds details a lay plan has to absorb:
- The favourite's price, not its reputation. A favourite priced under $2.00 should win more often than it loses if its price is fair, so a lay of it should lose more often than it wins. A rule such as "favourites lose more races than they win" says nothing about the price of the favourite in front of you.
- Scratchings. A runner scratched after your lay is matched raises every other runner's chance. The exchange applies its own scratching rule to matched bets, commonly by reducing the prices of bets on the runners left in the race. It may also cancel unmatched ones, so read the rule before you lay.
- Place markets. Laying to place is a bet that the runner misses every paid place, so its fair price comes from a place chance, not a win chance.
- The jump. Everything here is placed before the jump, and each unmatched lay needs a jump setting you chose on purpose.
Strategy mistakes and what they cost
With illustrative prices and 8% commission:
- Judging a method by strike rate. A lay record that wins 84% of the time at $6.00 is losing, because break-even there is 5 / (5 + 0.92) = 84.5%. Is lay betting profitable shows how fast the break-even line climbs with the price.
- Using a fixed stake on long prices. Twelve $10 lays at $12.00 carry 12 x 10 x 11 = $1,320 of liability to keep 12 x 10 x 0.92 = $110.40, and that only if every runner loses.
- Raising liability after a loss. Doubling the next lay to win back a loss doubles the next loss too; the daily stop exists to prevent it.
- Buying a system on its headline. A record without each lay's price, stake and liability cannot show a profit, because the numbers that decide profit are missing.
Where B337 fits in a lay strategy
B337 does not place lays: there is no back or lay placement on Betfair in the product, so the strategy and every bet are yours, in your own exchange account. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
What the Terminal gives a layer is context. Betfair back and lay sit beside prices from 40+ bookmakers across racing and sports, along with flucs and closing lines: how bookmakers price a runner before you lay it, and where its price finished afterwards. Prices are read on a repeating cycle, so confirm each one on the exchange.
Risk: Betting involves risk. Seeing bookmaker prices beside the exchange does not make a lay right, a liability can run to several times the stake, and past results are no guarantee of future results. See responsible gambling for limits and support.