Middle betting in Australia
A middle is two bets on opposite sides of the same total or line at two bookmakers: on most results one wins and the other loses, so at ordinary prices it costs a little, and only a result between the lines wins both. With $100.00 a side at $1.95 a miss costs $5.00 and a hit makes a $190.00 profit ($390.00 back on $200.00 staked), so the gap must land about 2.6% of the time to break even.
By the B337 team. Last updated .
The short answer
- A middle is two bets at two bookmakers whose lines leave a gap. On most results one leg wins and the other loses, so the position loses a little; only a result in the gap wins both.
- In the example below, $100.00 a side on a three-point gap costs $5.00 when it misses, which is the normal outcome, and makes a $190.00 profit when it lands.
- So it needs to land about 2.6% of the time to be worth nothing at all, and more than that to be worth having.
- A middle is not an arbitrage. An arb covers every outcome; a middle at ordinary prices leaves most of them paying a small loss.
What is middle betting?
Australian bookmakers set their own lines on totals and handicaps, and they do not always set the same one. When two of them are far enough apart, you can take the over at the lower line with one and the under at the higher line with the other. Every result between the two lines wins both bets. That space is the middle, and betting both sides of it is called middling.
On a total points market, with hypothetical lines of over 200.5 at one bookmaker and under 203.5 at another, the gap is 201, 202, 203. On a handicap, the same idea applies to the margin: back the underdog on the larger start at one bookmaker and the favourite on the smaller one at another, and a result in between pays twice.
Why it is not an arbitrage
An arbitrage bet is built so that every outcome returns more than the total staked. A middle is built the other way round: it accepts a small loss on most results to buy a double win on a few. Most of the time a middle misses, so the question is whether the gap lands often enough to pay for all the times it does not. The two only overlap when both prices add to under 100%, such as $2.05 a side: a miss then still pays a little on paper, and the screener shows that pair as a positive middle percentage.
Betting involves risk. Bookmakers can restrict or close accounts and void bets, automation can fail, prices move, and a positive expected value (+EV) bet can still lose. Promotions carry each bookmaker's own terms. There is no guarantee of profit. An arbitrage or a middle only works if every bet is accepted at the price shown. See responsible gambling for limits and support.
The maths: the gap, the cost and the hit rate
Hypothetical lines and prices, chosen to show the arithmetic. Not a real market, a real price or a forecast.
Take $100.00 on each side of that total: over 200.5 at $1.95 with one bookmaker, under 203.5 at $1.95 with another. $200.00 is staked across the two, and because every total wins at least one leg, the most it loses if both bets stand is $5.00.
| Result | Net on $200.00 staked |
|---|---|
| The total is 200 or less: the under wins, the over loses | -$5.00 |
| The total is 204 or more: the over wins, the under loses | -$5.00 |
| The total lands on 201, 202, 203 (in the gap): both legs win | +$190.00 |
| Break-even hit rate | 2.6% |
Miss the gap either way and one leg's winnings fall short of the other leg's stake: $100.00 x 0.95 = $95.00 against the $100.00 lost on the other side, so the position is -$5.00. That is the result to expect on any given match. Land in the gap and both legs pay, so the profit is $100.00 x 0.95 x 2 = +$190.00 on $200.00 staked.
The only number worth judging a middle by
Set the two together and solve for the hit rate that makes them cancel. The sum is the loss on a miss divided by the swing between the two outcomes, so $5.00 divided by $195.00 is 2.6%: above that rate the middle has value, below it the small losses win.
Nothing about that figure tells you whether three points of a total lands that often. To test a gap, count it among games priced like this one: from the competition's official results, take the games whose line sat close to this one, work out how often the result finished inside a gap of the same width in the same place against the line, and set that share against the break-even rate. That needs a record of past lines, not just results.
A season-wide count of every game that landed on 201, 202, 203 answers a different question, usually with a much smaller number, because most of those games were priced nowhere near 200.5: a total lined at 230 sits 28 points from this gap, while one lined at 202 sits inside it.
What the prices do to the bar
Prices move the bar a long way. Take the same gap at $1.85 a side instead: a hit makes $100.00 x 0.85 x 2 = +$170.00 while a miss costs $100.00 - $85.00 = $15.00, so the break-even rate rises to $15.00 / ($170.00 + $15.00) = 8.1%. Ten cents off each price more than triples how often the gap has to land, which is why both prices matter as much as the width of the gap.
With different prices on the two legs, the two misses no longer cost the same, and the stakes can be skewed to even them up. The free arbitrage and dutching calculators do that kind of split.
Betting involves risk. Bookmakers can restrict or close accounts and void bets, automation can fail, prices move, and a positive expected value (+EV) bet can still lose. Promotions carry each bookmaker's own terms. There is no guarantee of profit. A middle loses on most results by design, unless the two prices add to under 100%. Past results are no guarantee of future results. See responsible gambling for limits and support.
Where middles appear in Australian markets
Middles come from bookmakers disagreeing about a line.
- AFL and NRL totals and handicaps. The two codes carry lines all season at the major bookmakers, and a point or two of disagreement can appear in the days before a game rather than close to the start.
- Basketball totals. High totals move in larger steps, so gaps open wider, but a wide gap on a high total is not necessarily a likelier gap than a narrow one on a low total.
- Cricket totals and soccer goal lines. Both are sold on lines that differ between bookmakers, and both have settlement rules worth reading first.
- Smaller competitions. Lower leagues and state competitions are priced by fewer bookmakers and can carry lower maximum stakes.
Line moves after news are where gaps come from and where they go: one bookmaker reacts to a late out or a weather report and the other does not. A gap still open an hour later is worth a second look rather than a faster click. Racing win markets have no line at all, so middles are a sports play.
A line middle on a football margin
Same arithmetic, on a margin instead of a total: Team B at -9.5 with one bookmaker at $1.92, Team A at +12.5 with another, $100.00 a side. A miss costs $100.00 - $92.00 = $8.00 and a hit makes $92.00 x 2 = $184.00, so the break-even rate is $8.00 / ($184.00 + $8.00) = 4.2%. AFL line middles runs the count above on AFL margins, which are lined the same way.
| Result | Net on $200.00 staked |
|---|---|
| Team B wins by 13 or more: the -9.5 wins, the +12.5 loses | -$8.00 |
| Any other result, a draw included: the +12.5 wins, the -9.5 loses | -$8.00 |
| Team B wins by 10, 11 or 12 (in the gap): both legs win | +$184.00 |
| Break-even hit rate | 4.2% |
Building a middle bet from a line move
Take one side early at a number you like, and if team news moves the market past it, take the other side at the new number: the space between your two numbers is the middle. Until the second bet is on you hold an ordinary single bet, and if the line moves the other way there is no middle to build.
Betting involves risk. Bookmakers can restrict or close accounts and void bets, automation can fail, prices move, and a positive expected value (+EV) bet can still lose. Promotions carry each bookmaker's own terms. There is no guarantee of profit. Until the second bet is on you hold a single bet, and the line can move against it as easily as past it. See responsible gambling for limits and support.
Middle betting risks
A middle has one failure mode the arithmetic does not show: the two legs turning out not to be two sides of one question.
A push on a whole-number line
A whole-number line can land exactly on its number, and that leg is then refunded under the bookmaker's rules. In a middle that is usually a half-hit rather than a loss: with hypothetical lines of over 200 and under 203 at $1.95 and $100 a side, a total of exactly 200 refunds the over while the under wins, +$95.00 instead of +$190.00. Half-lines cannot push.
Two bookmakers settling differently
Extra time or overtime, abandoned matches, rain-shortened cricket, retirements and what counts towards a total are each bookmaker's own rules. Two legs on one event can settle on two different definitions.
The gap closing while you place
The second line is the one that moves. Taking one side and finding the other has moved to the same line leaves a flat bet, not a middle, at a price chosen for a different purpose.
Account restrictions
Taking the odd line at two bookmakers, again and again, is a visible pattern. Australian bookmakers can cut your maximum stake, stop offering promotions, void bets or close the account under their own terms, and many restrict or prohibit automated or third-party betting, including software placing bets in your account.
Judging it on one result
The payoff is lumpy: many small losses and an occasional large win. A dozen misses in a row does not by itself show the gap was priced badly, so decide before you start how much you can afford to lose on misses, and stop there rather than raising stakes to win it back.
Reading the middle percentage as a chance
On a screener, a middle percentage is the profit or loss per $100 staked when the middle misses. It is not the chance of landing in the gap, and the two should never be confused.
Where B337 fits
The middles screener does the search: it reads the totals and handicaps on the Terminal, B337's board of racing and sports prices from 40+ bookmakers beside exchange back and lay prices, and lists pairs of lines at two bookmakers that leave a gap. B337 is software you run yourself, not a bookmaker, and your money stays in your own accounts.
Its middle percentage is the profit or loss per $100 staked when the middle misses and only one leg wins, scaled to $100 of total stake: the example above, -$5.00 on $200.00 staked, shows there as -2.5%. It is not a probability, and the screener does not tell you how often a gap lands: that judgement stays yours. The arbitrage and positive EV screeners sit beside it.
B337 does not place middles automatically. There is no middles strategy in the bot: the screener finds the pairs and placing both legs is yours to do, by hand or on Terminal Pro by clicking a price on the board, one leg at a time, in a bookmaker account attached to your B337 bot, which runs on your own computer. Terminal Pro is $300 a month, and bets placed through B337 use credits, a per-bet usage charge on top of the plan price. The screeners are a plan of their own and are included with Terminal Pro and Full Automation: see pricing.
See the middles screener's rows
The live count of middles shows on a free account; the pairs behind it, with both lines, both bookmakers and both prices, come with Terminal Pro, Full Automation or the Screeners plan. Without an account, the lay, arbitrage, dutching and racing promo calculators still work.
- Pairs of lines on one market that leave a gap between them
- Middle % is the profit or loss per $100 staked when the middle misses
- The +EV and arbitrage screeners beside it
Betting involves risk. Bookmakers can restrict or close accounts and void bets, automation can fail, prices move, and a positive expected value (+EV) bet can still lose. Promotions carry each bookmaker's own terms. There is no guarantee of profit. For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au. See responsible gambling for limits and support.
Common questions
Is middle betting profitable?
Only when the gap lands more often than the break-even rate, and that is a judgement about the sport, not an output of the arithmetic. The maths tells you the rate you need. Whether a three-point gap in a particular competition clears it is the part you have to be right about, and nobody can promise you are.
What does middling mean in betting?
Middling is the same thing as middle betting: one bet on each side of a line or total, at two bookmakers whose numbers leave a gap, so a result in the gap wins both. The middle is the gap itself, and middling is betting both sides of it.
Can a middle be hedged if the gap closes?
If the gap closes before your second bet is on, you hold a single bet, not a middle. Taking the other side at the new line caps the result, but if that line has moved past yours both bets lose on the numbers in between, so price every result before you place it. Laying is only possible on an exchange that lists the market.
Can you middle player lines like AFL disposals?
Yes, when two bookmakers set different numbers for the same player, and the same break-even test applies. Whole-number player lines can push, and what happens when a player does not take the field is each bookmaker's own rule, so read both sets of terms before you count on a gap.
Keep reading
Start with a free account
A free account opens a limited view of the Terminal with live odds, and the middles screener's live count. Terminal Pro, Full Automation or the Screeners plan show the pairs behind it; Terminal View, the read-only board, does not include the screeners.