AFL middle betting is backing a favourite to cover the line at one bookmaker and its opponent on a bigger start at another. Every margin outside the two numbers costs you a little, because one bet wins and the other loses; a margin between them wins both. With Team B at -9.5 at one bookmaker and Team A at +12.5 at another, that is a Team B win by 10, 11 or 12 points.
An AFL middle loses on most results by design. Measured against a forecast built from the AFL's own results, a 3-point gap lands roughly 1 game in 27, so the question is whether the two prices pay enough for how rarely that happens. Middle betting in Australia covers middles across sports. In AFL betting the twist is that margins have no key numbers, so a gap's width matters far more than where it sits.
How two AFL lines make a middle at -9.5 and +12.5
Say Bookmaker A has Team B at -9.5 and Bookmaker B has Team A at +12.5, both at an illustrative $1.90, and you put $50 on each: $100 staked across two accounts.
| Final margin | Team B -9.5, $50 at $1.90 | Team A +12.5, $50 at $1.90 | Net on $100 staked |
|---|---|---|---|
| Team B by 13 or more | Wins, returns $95 | Loses | -$5 |
| Team B by 1 to 9 | Loses | Wins, returns $95 | -$5 |
| Draw | Loses | Wins, returns $95 | -$5 |
| Team A wins | Loses | Wins, returns $95 | -$5 |
| Team B by 10, 11 or 12 | Wins, returns $95 | Wins, returns $95 | +$90 |
Team B -9.5 needs a win by 10 or more, and Team A +12.5 holds on any Team B win of 12 or fewer. A draw is a margin of 0, which pays the side receiving points, as AFL line betting explains.
Example: Illustrative prices, not a real game or a current market. Each winning leg returns $50 x 1.90 = $95. A miss returns $95 on $100 staked, a $5 loss; a hit returns $95 + $95 = $190, a $90 profit.
Risk: Betting involves risk. Most margins cost the $5, and the $90 needs both bets to stand at the prices shown. See responsible gambling for limits and support.
The cost of a miss against the both-win result
The hit has to pay for every miss:
break-even hit rate = cost of a miss / (profit on a hit + cost of a miss) = 5 / (90 + 5) = 5.26%
With the same price on both sides that reduces to (2 - price) / price. With $50 a side:
| Price on each side | A miss costs | A hit makes | Break-even hit rate |
|---|---|---|---|
| $1.85 | $7.50 | $85.00 | 8.11% |
| $1.90 | $5.00 | $90.00 | 5.26% |
| $1.94 | $3.00 | $94.00 | 3.09% |
| $1.95 | $2.50 | $95.00 | 2.56% |
At $2.00 a side a miss costs nothing on paper, and above it the two prices add up to under 100%: an arbitrage with a middle on top, if both bets stand. A middle at ordinary prices is not an arbitrage.
Tip: With unequal prices, split the stake in proportion to the other leg's price. At illustrative prices of $1.87 and $1.96, $51.17 and $48.83 return $95.69 and $95.71, so a miss costs about $4.30, against $6.50 or $2.00 at $50 a side; the dutching calculator does the split.
Risk: Betting involves risk. An arbitrage or a middle only works if every bet is accepted at the price shown. See responsible gambling for limits and support.
How often an AFL gap lands, measured
The hit rate decides a middle, so it has to be measured rather than assumed. The AFL publishes results, not betting lines, so this measurement uses a stand-in for the line, a margin forecast built only from games already played:
- The data: the AFL's home-and-away results from 2013 to 2026, 2,609 games, with 2012 used to start the ratings. Games from 2020 are not counted, because the AFL cut that season's quarters from 20 to 16 minutes.
- The forecast: the gap between the two clubs' ratings in points, plus 8 points to a side at home in its own state against an interstate visitor, or 2 in a same-state game. After every game, finals and 2020 included, both ratings move by 9% of the forecast's miss, and they shrink 40% towards average between seasons, settings fitted to 2013 to 2019 only.
- The count: how often the final margin landed inside a window of a given width, centred on the forecast.
| Gap width (margins inside it) | Example pair | Games inside the window | Share of 2,609 games |
|---|---|---|---|
| 1 | -9.5 and +10.5 | 32 | 1.23% |
| 2 | -9.5 and +11.5 | 61 | 2.34% |
| 3 | -9.5 and +12.5 | 96 | 3.68% |
| 4 | -9.5 and +13.5 | 123 | 4.71% |
| 5 | -9.5 and +14.5 | 158 | 6.06% |
| 6 | -9.5 and +15.5 | 193 | 7.40% |
Each point of width added about 1.2 percentage points, up to an 11-point window that caught 13.1%. The two halves of the record differ: a 3-point window caught 3.2% of games from 2013 to 2019 and 4.2% from 2021 to 2026, so read 3% to 4% as the honest range.
Where the gap sits matters far less. Three-point windows centred anywhere from 15 points below the forecast to 15 points above it caught between 2.9% and 4.4% of games. With goals worth 6 and behinds 1, an AFL score can stop on almost any margin, unlike the NFL, where 14.6% of 2021 to 2025 regular-season games finished exactly 3 points apart (NFL key numbers).
A bookmaker's line also uses team news this forecast cannot see, so the rate at a real line can differ from the table either way. To test your own gaps, record the line of every game you look at and count how often the official margin minus that line lands in your gap's window. Over a few hundred games, compare that share with your break-even rate.
Note: The forecast is a simple model, not a bookmaker's line, and the counts come from the AFL's published results, checked October 2026. Past results are no guarantee of future results.
What price each AFL gap width needs
The break-even price on each side is 2 / (1 + hit rate), so a 3-point gap needs 2 / 1.0368 = $1.93 a side:
| Gap width | Measured hit rate | Break-even price on each side | Average result at $1.90 a side, per $100 staked |
|---|---|---|---|
| 1 | 1.23% | $1.98 | -$3.83 |
| 2 | 2.34% | $1.95 | -$2.78 |
| 3 | 3.68% | $1.93 | -$1.50 |
| 4 | 4.71% | $1.91 | -$0.52 |
| 5 | 6.06% | $1.89 | +$0.75 |
| 6 | 7.40% | $1.86 | +$2.03 |
The last column is hit rate x $90 - miss rate x $5, worked from the game counts rather than the rounded percentages. At $1.90 a side, a gap needs to be about 5 points wide before its average result turns positive.
Half point middles and whole-number lines
The narrowest AFL middle sits a half point either side of one margin, such as -9.5 against +10.5, which wins both bets on a 10-point win only. At 1.23% it needs about $1.98 a side.
Whole-number lines turn the ends of a gap into half-hits. With Team B -10 and Team A +12 at $1.90, $50 a side, an 11-point win pays both bets (+$90). At 10 the -10 pushes, and at 12 the +12 pushes, each making $95 + $50 - $100 = +$45 if the push returns the stake.
At 1.23% a margin, those two half-hits cost about 2 x 1.23% x $45 = $1.11 per $100 against -9.5 and +12.5, for an average of about -$2.60. Check how each bookmaker settles a push.
Risk: Betting involves risk. A measured hit rate describes past games, not the next one, and a gap that pays on average still misses on most results. There is no guarantee of profit. See responsible gambling for limits and support.
Lines moving after selections: where AFL gaps open
Gaps can open around team news, which the AFL Regulations (11 February 2026 version) put on a timetable. AFL team selections and betting sets out Thursday's team lists and the team sheet due an hour before the start. A gap appears when one bookmaker moves its line on the news and another has not yet.
A gap can also be built over the week. Say you took Team B -9.5 at an illustrative $1.90 on Monday, then Team B's key forward is named to return on Thursday and the market moves to Team B -13.5, $1.90 a side. At about 1.2 percentage points a point, your -9.5 now covers about 50% + 4 x 1.2% = 54.8% of the time:
| Position | Expected value |
|---|---|
| Hold Team B -9.5 alone, $50 | 0.548 x 1.90 - 1 = +4.12c per $1, +$2.06 |
| Add Team A +13.5 at the new price, $50 | 0.500 x 1.90 - 1 = -5c per $1, -$2.50 |
| Hold both: the middle | +$2.06 - $2.50 = -$0.44 on $100 |
A middle's expected value is the sum of its two bets. The second bet narrows your results from +$45 or -$50 to +$90 or -$5, but it pays the bookmaker's margin again, so it adds value only when its own price is at or above fair. If the line moves the other way there is no middle at all, and online betting on a match closes when it starts (Interactive Gambling Act 2001, s 8A(3) and s 10B).
Risk: Betting involves risk. Between your first and second bet you hold one open position, and the line can move away from it. See responsible gambling for limits and support.
Rules that can break an AFL middle
- Draws. A level score is a margin of 0, outside any gap on one team's side. AFL draw rules covers how a drawn game settles.
- Finals. A final level at the siren goes to extra time (Regulation 2.8). The NSW Bookmaker Declared Betting Events Betting Rules count it in line bets unless agreed otherwise (clause 5.1.3), other bookmakers set their own rules, and two legs can be settled on two different scores.
- Stopped games. A home-and-away game stopped before half time that cannot restart within 60 minutes, or another period the AFL sets, is deemed a draw (Regulation 33.2(b)), and one bookmaker may settle on that while the other refunds.
- Bookmaker terms. An account that keeps taking the stray number stands out. Bookmakers can cut stakes, void bets or close accounts under their own terms, and many restrict or prohibit automated or third-party betting, software that places bets in your account included.
Mistakes that turn an AFL middle into a loss
| Mistake | What it costs, on the $50-a-side example |
|---|---|
| Reversing the signs: Team B -12.5 and Team A +9.5 | A Team B win by 10 to 12 loses both bets, -$100 |
| Taking $1.85 a side on a 3-point gap | The bar rises to 8.11% against a measured 3.68%: about -$4.10 per $100 on average |
| Judging a middle by its hit | At a 3.7% hit rate, 27 tries average one hit (+$90) and 26 misses (-$130), -$40 in all |
Skip a middle when its gap is narrower than its prices allow or you cannot read both bookmakers' settlement rules. If your real view is that the game finishes inside a band, AFL margin betting backs it with one bet.
Finding AFL middles with the middles screener
B337's middles screener looks across the sports markets on the Terminal for pairs of lines on one total or handicap, at two bookmakers, with a gap between them. Its middle percentage is the profit or loss per $100 staked when the middle misses and one leg wins: -5.0% for the example at $1.90. That figure is not a probability, and the screener does not say how often a gap lands: that judgement stays yours.
There is no middles strategy in the bot: you place each leg yourself, by hand or from the board on Terminal Pro, one leg at a time. Terminal Pro needs a bookmaker account attached to your B337 bot, which runs on your own computer.
The screeners are part of Terminal Pro and Full Automation, and sold on their own as the Screeners plan; a free account shows the live counts with the rows locked. Bets placed through B337 use credits, a per-bet usage charge. For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au.
Risk: Betting involves risk. A middle loses on most results by design, and either bookmaker can cap your stake, void a bet or close your account. See responsible gambling for limits and support.