AFL Line Betting Calculator
Enter an AFL handicap, the price and your stake, then a projected margin, and see whether the line covers, what the bet returns and the win probability that line implies.
Line Betting Calculator
Inputs
Signed, so -18.5 for a favourite and +18.5 for an underdog.
Your own projection for the selected team, negative if you have them losing.
Default 37.7, the published Matter of Stats figure from 2006 to 2009 empirical handicap-adjusted margins.
Results
Line covers by 6.5 points
Projected winning margin of 25.0 points against a handicap of -18.5.
- Adjusted margin
- +6.5
- Total return
- $95.00
- Profit
- +$45.00
- Break-even strike rate
- 52.63%
Projected margin plus the handicap
Stake and profit combined
Implied probability of the price
- Modelled cover chance
- 56.84%
- Push chance
- 0.00%
- Edge over break-even
- +4.21%
- Expected value
- +$4.00
Normal model on the adjusted margin
Half point line, so a push is impossible
Cover chance less the break-even rate
On this stake, at the modelled cover chance
What the modelled cover chance assumes
The cover chance is PHI((L - h) / sigma), where L is the projected margin, h is the line the selection has to beat and PHI is the standard normal cumulative distribution. It rests on the published finding that handicap-adjusted AFL margins are close to normal.
- Sigma is not constant. The default of 37.7 points is the published Matter of Stats figure from 2006 to 2009 empirical handicap-adjusted margins, and per-match standard deviation varies widely around it, so treat 37.7 as an average and change it if you have a better one.
- The posted line already contains the bookmaker margin, so a probability derived from a line is a price, not a fair probability.
- Normality degrades in the tails, so cover chances a long way from even money are the least reliable numbers on this page.
- Settlement rules vary. Extra time counts towards handicap settlement and abandoned matches usually void handicap bets, so check the terms at your bookmaker.
How the AFL Line Betting Calculator works
A line bet applies a handicap to the final margin before the bet is settled. Backing a favourite at minus 18.5 means adding minus 18.5 to their winning margin: they must win by 19 or more for the bet to pay. Backing the underdog at plus 18.5 means they can lose by up to 18 and the bet still collects.
AFL lines are usually set at a half point so there is no possibility of a push, and both sides are typically priced close to even money. Because the price is close to 1.90 on both sides, the break-even strike rate sits just above 52 per cent, which is the number a line bettor has to clear rather than a simple win rate.
Adjusted margin = actual margin + handicap Covered when adjusted margin > 0 Return = stake x odds Break-even win rate = 1 / odds x 100
Example
A handicap of -18.5 at 1.90 with a $50 stake, against a projected winning margin of 25 points, gives an adjusted margin of +6.5, so the line covers. The bet returns $95.00 for a profit of $45.00, and the break-even strike rate at that price is 52.63%.
How to use it
- Enter the handicap as a signed number, for example -18.5 for a favourite.
- Enter the decimal price on that line, for example 1.90, and your stake.
- Enter the winning margin you are projecting, for example 25.
- Read whether the line covers, the return and the break-even strike rate.
AFL Line Betting Calculator FAQ
Why are AFL lines set at half points?
A half point removes the possibility of the final margin landing exactly on the handicap. If a line were set at 18 and the favourite won by 18, the bet would be a push and stakes would be refunded, which complicates settlement and reduces turnover. Setting the line at 18.5 guarantees one side wins and the other loses. Some bookmakers do offer whole number lines with a push rule, so check the terms if the line you are quoted has no half point.
What break-even strike rate does a line bet need?
It is the implied probability of the price you take. At 1.90 you need to win more than 52.63 per cent of your line bets to break even, and at 1.95 you need more than 51.28 per cent. That few per cent above a coin flip is the bookmaker margin, and it is the entire hurdle in line betting. Because the prices are close to even money on both sides, small improvements in the price you take have a large effect on the long-run result.
How does a line bet differ from a head-to-head bet?
A head-to-head bet settles on who wins, at prices that reflect how likely each team is to win. A line bet settles on the margin relative to a handicap, at prices close to even money on both sides. The line is the estimate a bookmaker makes of the margin that makes the two sides equally likely. Line betting therefore shifts the question from which team is better to whether the market has the size of the gap right.
What happens to a line bet if the match is abandoned?
Treatment depends on the bookmaker and on how much of the match was played. Common rules include voiding all bets if the match is not completed, or settling on the score at the time of abandonment if a defined portion of the match has been played. AFL matches are rarely abandoned but weather delays do occur. Since the outcome differs between operators, the settlement terms are worth reading before placing a line bet on a match with a genuine weather risk.
Can I use this for AFL alternate lines?
Yes. Alternate lines are the same bet with a different handicap and a correspondingly different price, so the arithmetic is identical: add the handicap to the projected margin and check the sign. What changes is that alternate lines move away from even money, so the break-even strike rate moves with them. A heavily shortened alternate line needs a much higher strike rate, and a long one needs much less, which the calculator reports for whatever price you enter.
Gamble Responsibly
Think! About your choices. Set a deposit limit. Gambling problem? Call Gambler's Help 1800 858 858 or visit gamblinghelponline.org.au. Odds and markets shown for informational purposes only. OzFootball Stats does not accept wagers. 18+ only.