Line shopping in betting means checking what several bookmakers offer on the same bet and placing it wherever the price is highest. Your selection, stake and result stay the same, and only the return changes: with illustrative prices, 100 bets of $50 with 52 winners lose $60 at $1.90 and make $70 at $1.95.
The term is American, where a line is any price. Australians tend to call it comparing prices or shopping for the best price, and here a line is also the handicap market, where you shop for the number as well as the price. Price is the part of a betting strategy you control most directly, though a better price beats the margin only once it is above the fair price.
How to compare prices like with like
Comparing prices pays because bookmakers do not have to agree. Each sets its own price, or follows another market with its own margin added, and moves at its own pace, so one runner or team can carry several prices at once. Bookmaker margin shows how to measure what each one builds in, and no single bookmaker has the top price on everything, as which bookmaker has the best odds explains.
Compare like with like: the same selection, market and line or total number. Settlement rules must match too, since each bookmaker's terms decide dead heats, scratchings, extra time and players who do not play. Leave boosts out: a boost is a promotion on one bet, not a market price.
Comparing prices on both sides of a market shows how much margin the best prices leave you paying. With illustrative prices, Bookmaker A offers $1.97 and $1.84 on a two-team game, a book of 1 / 1.97 + 1 / 1.84 = 105.11%, and Bookmaker B offers $1.89 and $1.92, a book of 104.99%. Taking $1.97 from A and $1.92 from B makes a combined book of 102.84%, so the excess over 100% falls from about 5 points to 2.8. The bookmaker margin calculator runs that sum for any prices.
Risk: Betting involves risk. A smaller margin is not an edge: the best price can still sit below fair and lose on average. See responsible gambling for limits and support.
The same 100 bets at $1.90 and at $1.95
Take one set of 100 bets of $50 on two-way markets, $5,000 staked, and suppose 52 of them win. With illustrative prices and results:
| Measure | At $1.90 | At $1.95 |
|---|---|---|
| Return: 52 winners x $50 x price | $4,940 | $5,070 |
| Profit: return - $5,000 | -$60 | +$70 |
| Yield: profit / $5,000 | -1.2% | +1.4% |
| Break-even strike rate: 1 / price | 52.6% | 51.3% |
| Winners out of 100 needed to finish ahead | 53 | 52 |
The $130 between the columns is the extra 5 cents on each winner: 52 x $50 x 0.05 = $130. Fifty-two winners fall short of the 52.6% that $1.90 needs and clear the 51.3% that $1.95 needs, so the same judgement loses at one price and wins at the other.
Risk: Betting involves risk. A better price raises what each winner returns, not how often you win, and 52 winners in 100 can swing by five either way through luck alone. See responsible gambling for limits and support.
Why small price gaps add up
A price 2.6% higher (1.95 / 1.90 - 1) pays 2.6% more on every winner, so it lifts your total return by 2.6% whatever your strike rate. Per $1 staked the extra is strike rate x price gap: at 52%, 0.52 x 0.05 = 2.6 cents, which is $130 on $5,000 staked, $520 on $20,000 and $1,300 on $50,000.
Longer prices can open bigger gaps. With illustrative prices and strike rates:
| Bet | Lower price | Best price | Higher by | Strike rate | Return per $1, lower | Return per $1, best | Extra per $1,000 staked |
|---|---|---|---|---|---|---|---|
| Head to head | $1.90 | $1.95 | 2.6% | 52% | 98.8c | 101.4c | $26 |
| Race favourite | $3.30 | $3.50 | 6.1% | 29% | 95.7c | 101.5c | $58 |
| Long shot | $13.00 | $15.00 | 15.4% | 6.4% | 83.2c | 96.0c | $128 |
Return per $1 = strike rate x price, so the long shot returns 0.064 x 15.00 = 96.0 cents at its best price: it gains the most and still loses. Long prices can carry more of a market's margin, the favourite-longshot bias, so check them against a fair price too.
Multis compound the gap, because the legs' prices multiply. With illustrative prices, three legs at $1.90 combine to 1.90 x 1.90 x 1.90 = $6.86, and three at $1.95 to 1.95 x 1.95 x 1.95 = $7.41. A $20 multi then returns $20 x 1.95 x 1.95 x 1.95 = $148.30 instead of $20 x 1.90 x 1.90 x 1.90 = $137.18, 8.1% more from three gaps of 2.6% (1.0263 x 1.0263 x 1.0263 = 1.081).
Risk: Betting involves risk. The extra from better prices is an average over many bets, a multi still loses if any leg loses, and there is no guarantee of profit. See responsible gambling for limits and support.
The best price against the fair price
Shopping shrinks the margin you pay; beating it takes a price above the fair price, 1 / the result's true chance. Suppose your best estimate of a team's chance is 51%, a fair price of 1 / 0.51 = $1.96. With illustrative prices:
| Price taken | Expected profit per $100: 0.51 x price x $100 - $100 |
|---|---|
| $1.86 | -$5.14 |
| $1.90 | -$3.10 |
| $1.95 | -$0.55 |
| $1.98 | +$0.98 |
The best of the first three still loses on average, and only the price above $1.96 carries an edge. That is the line between shopping and value betting, which starts from a fair price and takes only prices above it.
Closing line value measures the price you took against the last price before the start. With illustrative prices, a $1.95 bet on a team that closes at $1.90 beats the close by 1.95 / 1.90 - 1 = 2.6%, before any margin comes out of the close.
Risk: Betting involves risk. A fair price is an estimate, a +EV bet can still lose, and often does, and beating the close measures your prices, not your balance. See responsible gambling for limits and support.
Lines and totals: when half a point beats a better price
On a line or a total, compare the number before the price. A line changes the result on one margin only: Team A -5.5 wins on a 6-point win that Team A -6.5 loses, so -6.5 at $1.94 against -5.5 at $1.85 turns on how often Team A wins by exactly 6. With illustrative chances, Team A covers -6.5 half the time:
| Chance Team A wins by exactly 6 | -6.5 at $1.94, return per $1 | -5.5 at $1.85, return per $1 | Better bet |
|---|---|---|---|
| 1% | 0.50 x 1.94 = 97.0c | 0.51 x 1.85 = 94.4c | -6.5 at $1.94 |
| 6% | 0.50 x 1.94 = 97.0c | 0.56 x 1.85 = 103.6c | -5.5 at $1.85 |
The half point is worth its cost when an exact 6 is more likely than 0.50 x (1.94 - 1.85) / 1.85 = 2.4%. In rugby league, where a converted try is worth 6, margins bunch on even numbers and a half point either side of 6 can be worth far more than a few cents of price, as NRL line betting measures. In the AFL, where a game can end on almost any margin, an exact 6 is far less likely to clear it.
Totals work the same way: over 40.5 and over 41.5 differ only on a total of exactly 41. For bookmakers authorised in NSW, the state's Bookmaker Declared Betting Events Betting Rules set a points start at half a point unless bookmaker and customer agree otherwise (clause 5.1.3), and half point lines explains pushes on whole numbers.
Risk: Betting involves risk. The margin chances behind a half point are estimates, and a bet on the better line can still lose. See responsible gambling for limits and support.
Practical limits: accounts, stakes and time
Accounts in your own name
Every account must be in your own name, and under the National Consumer Protection Framework your identity has to be verified before you can place a bet. Your money then sits in several accounts, and any deposit limit is set with each bookmaker separately: a decrease applies at once, an increase only after 7 days. More accounts do not always mean more prices, because brands on one shared betting platform can show the same prices; see white label bookmaker.
Stake limits on the best price
Each bookmaker sets a maximum bet on a market, and its terms generally let it cut what an account may stake, so the best price can come with the smallest limit. Racing is a partial exception: racing bodies including Racing Victoria and Racing Queensland set minimum bet limits, under which off-course operators must accept eligible fixed-odds bets until they stand to lose a set amount (checked October 2026). A limit is not something to get around with a second account, or anyone else's account or identity.
The time a comparison takes
Checking six bookmakers by hand takes minutes, long enough near the start for prices to move. Some gaps are not worth the hunt: one cent at $1.90 is worth 0.52 x 0.01 = about half a cent per dollar at a 52% strike rate, which no rushed bet or money transfer repays.
Prices move, so confirm the price before you bet
A price on any comparison is a snapshot, and your bet is struck at the price the bookmaker accepts. For bookmakers authorised in NSW, the events rules treat the payout quoted when a sports bet is made as the one agreed, except for an error caused by a computer or other technical malfunction, or fraud (clause 5.1.5). Check the price on the bet slip and in your bet history.
Three cases change what a best price is worth:
- A price far above every other bookmaker can be an old quote or a mistake: check your bookmaker's terms on a palpable error before relying on it.
- A winning fixed-odds racing bet struck before a late scratching is paid less a deduction the stewards declare, however good its price was, as scratchings and deductions shows.
- Online sports bets with Australian bookmakers are allowed only before the event begins (Interactive Gambling Act, s 10B and s 8A(3)), so shopping on a game ends at the start.
Tip: Note the price you saw and the price you got on every bet; if they often differ, compare closer to the moment you bet.
Mistakes that give the gap back
| Mistake | What it costs |
|---|---|
| Treating -6.5 and -5.5 as the same bet | Every exact 6: 97.0 against 103.6 cents per $1 in the 6% row of the half-point table |
| Shopping only on short prices | The long shot gained 12.8 cents per $1 from shopping, the head to head 2.6 cents |
| Opening more accounts than your budget keeps funded | The second-best price on exactly the bets the gap was for: fewer accounts, each funded within your own deposit limit, keep the gap |
Risk: Betting involves risk. Shopping lifts a long shot's return, not its chance: the example's long shot still lost about 4 cents a dollar at its best price. See responsible gambling for limits and support.
Comparing prices on B337's Terminal
B337's Terminal sets prices from 40+ bookmakers across racing and sports side by side, each bookmaker in its own column, with the best available price picked out and Betfair back and lay beside them. For sport that means head to head, line and total markets, and player props where bookmakers offer them; not every bookmaker prices every race or game.
Prices are read on a repeating cycle, not tick by tick, so a price on screen can trail the bookmaker's own: confirm it in your bookmaker account before you bet. The free live odds comparison board shows two bookmakers' win and place prices on the next races, and a free account opens a limited view of the Terminal with live odds. Betfair is a trade mark of its owner, and B337 is not affiliated with it. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au.
Risk: Betting involves risk. The best price on a board is not a forecast, it can move before your bet is accepted, and bookmakers can limit stakes or void bets under their terms. See responsible gambling for limits and support.