Line betting is betting on a game with a head start built in: one team is given a start in points, and the bet settles on the final score with that start applied. The favourite gives the start, shown as a minus number such as -12.5, and the outsider receives it, +12.5. Team A at -12.5 has to win the game by 13 or more for the bet to pay, while Team B at +12.5 pays if it loses by 12 or fewer, draws or wins.
The start is set so each side is close to an even chance, which is why both sides of a line are priced near even money even when the head to head is lopsided. Points start is another Australian name for the same bet, used in the NSW rule book for sports bookmakers, and soccer and tennis call the idea a handicap.
Settling a -12.5 line: five final scores
To settle a line bet, apply the start to the score of the team you backed, then see who is ahead. With illustrative prices of $1.88 on Team A -12.5 and $1.94 on Team B +12.5, and $40 on each:
| Final score | Margin | Team A -12.5 at $1.88 | Team B +12.5 at $1.94 |
|---|---|---|---|
| Team A 96, Team B 80 | Team A by 16 | 96 - 12.5 = 83.5, ahead of 80: returns $75.20 | 80 + 12.5 = 92.5, behind 96: loses |
| Team A 89, Team B 76 | Team A by 13 | 89 - 12.5 = 76.5, ahead of 76: returns $75.20 | 76 + 12.5 = 88.5, behind 89: loses |
| Team A 88, Team B 76 | Team A by 12 | 88 - 12.5 = 75.5, behind 76: loses | 76 + 12.5 = 88.5, ahead of 88: returns $77.60 |
| Team A 81, Team B 81 | Draw | Loses | Returns $77.60 |
| Team A 70, Team B 75 | Team B by 5 | Loses | Returns $77.60 |
Return = stake x price, so $40 x 1.88 = $75.20, a $35.20 profit, and $40 x 1.94 = $77.60, a $37.60 profit. The rows for 13 and 12 show where the line splits: one point of margin decides both bets.
Half-point and whole-number lines: when a line bet pushes
A final margin is always a whole number, so a half-point line such as -12.5 can never land on it: every result has a winning side of the bet. NSW makes that the default for the sports bookmakers it authorises: under its Bookmaker Declared Betting Events Betting Rules, unless the bookmaker and customer agree otherwise, a points start is set to half a point (clause 5.1.3).
A whole-number line has three outcomes instead of two. At -12, Team A wins the bet with a 13-point win or more, loses it with 11 or fewer, and lands on the number with an exact 12-point win. That is a push, and the usual rule type refunds the stake: your $40 comes back with no profit. The rule is the bookmaker's to set, so check its terms.
| Team A's margin | Team A -12.5 | Team A -12 | Team B +12 |
|---|---|---|---|
| 13 or more | Wins | Wins | Loses |
| Exactly 12 | Loses | Push: stake back | Push: stake back |
| 11 or fewer, a draw or a loss | Loses | Loses | Wins |
Moving from -12.5 to -12 is worth exactly the chance of a 12-point margin, so the side that gains the refund is priced a little shorter. That chance is not the same on every number: rugby league margins bunch on even numbers, so a half point across 6 matters more than one across 5. Soccer's Asian handicaps go further, with quarter-goal lines that split your stake across two lines.
Why both sides of a line sit near even money
A head to head market moves the price to fit the teams: $1.30 on one and $3.60 on the other, say. A line market moves the number instead, until the two sides are roughly a coin toss, and the margin then sits in the prices. At $1.88 and $1.94, the implied probabilities are 1 / 1.88 = 53.19% and 1 / 1.94 = 51.55%, a book of 104.74%. A bookmaker that took balanced money on both sides would keep about 1 - 1 / 1.0474 = 4.5% of it.
Those implied probabilities are also the strike rates you need to break even: 53.19% of your bets at $1.88, and 51.55% at $1.94. When money arrives for one side, the bookmaker can shorten its price, from $1.88 to $1.83 for example, or move the number, from -12.5 to -13.5.
Line or head to head: converting is approximate
A fair line at -12.5 says the middle of the market's view is a Team A win by about 12.5: half the time by more, half the time by less. The head to head asks something else, whether Team A wins by any margin, and the answer depends on how widely results spread around that middle, which the line price does not tell you.
Assume, for illustration only, that margins spread around the middle in a bell curve, and try three spreads, each measured as a standard deviation (the typical distance between a result and the middle). Each chance is the share of the curve above a margin of 0. Divide the middle by the spread (12.5 / 20 = 0.625), then look that up in a normal table or a spreadsheet's NORM.S.DIST(0.625, TRUE), which gives 73.4%.
| Spread of margins (illustrative) | Chance Team A wins | Fair head to head price |
|---|---|---|
| 20 points | 73.4% | 1 / 0.734 = $1.36 |
| 30 points | 66.2% | 1 / 0.662 = $1.51 |
| 40 points | 62.3% | 1 / 0.623 = $1.61 |
On these three illustrative spreads, the same fair -12.5 line fits a head to head anywhere from $1.36 to $1.61. The spread differs by sport and by game, so a rule of thumb that converts lines to head to head prices in one sport misleads in another. Real margins are not a smooth curve either: bunching on key numbers, and the chance of a draw, both bend the conversion.
The useful check runs the other way. With both markets in front of you, subtract the line's 50% from the head to head's fair chance. What is left is the market's estimate of Team A winning by less than the start: at 66.2%, a Team A win by 1 to 12 is rated at 66.2% - 50% = 16.2%. If that looks wrong to you, one of the two prices is the one to look at.
Moving the start for a different price
An alternate line offers the same game at a different start, priced off the main line: the more points you take in your favour, the shorter the price. With illustrative prices around the -12.5 line at $1.88, Team A might be $1.55 at -6.5 and $2.35 at -18.5. Moving the number also moves the margin, usually wider the further you go from the main line, and the US name for paying to move a line is buying points. Pick your own line shows how those prices step and what the extra margin costs.
Lines across sports
The shape is the same in every sport; the scoring, the name and the rule that catches people out change. The sports betting explained hub maps the other markets each sport offers:
| Sport | What the line looks like | What can catch you out | Guide |
|---|---|---|---|
| AFL | A points start on the final score | Extra time in finals, and drawn home-and-away games | AFL line betting |
| NRL | A points start, with margins bunching on even numbers | Golden point | NRL line betting |
| NBA | A points start, called the spread in the US | Overtime | NBA line betting |
| NBL | The NBA shape, on Australia's own league | Overtime | NBL betting |
| Soccer | Asian handicap in half, whole and quarter goals | Settled at the end of normal time | Asian handicap explained |
| Tennis | A start in games, such as -3.5 games | A retirement before the match ends | tennis handicap betting |
| Baseball, ice hockey | The run line and the puck line | Extra innings and overtime | MLB run line, puck line |
Extra time, abandoned games and other edge cases
The NSW rule book settles these cases one way; bookmakers licensed elsewhere write their own rules, so read yours before you rely on any of them.
- Extra time counts. Unless agreed otherwise, a line bet includes any extra time, golden point or overtime played to decide the game (clause 5.1.3). Take an illustrative case: Team A -3.5 in a basketball game tied at the end of regulation that Team A wins by 6 in overtime. The bet wins if overtime counts, and loses if the market settles at the end of regulation, when the margin was 0.
- Soccer is settled at the end of normal time, in most games 90 minutes plus stoppage time, so extra time does not count (clause 5.2.7.3).
- A soccer match called off with an official result declared voids bets that depend on the number of goals, handicap bets included (clause 5.2.7.2).
- A game postponed and not rescheduled within three calendar days is treated as abandoned (clause 5.1.6), and bets on an abandoned or cancelled game are refunded (clause 5.1.10).
- In tennis, if a player retires, withdraws or is disqualified after the match has started, single bets on the match are void (clause 5.2.8.3). Otherwise, bets not decided when a match ends short of its scheduled sets are void (clause 5.2.8.2).
Postponed, relocated and abandoned games have their own guide: postponed and abandoned games.
Line bet mistakes and what they cost
| Mistake | What it costs (illustrative prices) | How to avoid it |
|---|---|---|
| Reading -12.5 as a 12-point win | A 12-point win loses the bet | The minus side needs the start rounded up: 13 |
| Ignoring the extra time rule | The -3.5 basketball bet above wins or loses on that rule alone | Read the extra time clause first |
| Comparing prices on different numbers | $1.88 at -12.5 and $1.97 at -13.5 are different bets: a 13-point win wins one and loses the other | Compare the number, then the price |
| Expecting a whole number to refund near misses | -12 refunds only an exact 12; an 11-point win still loses | Know which single margin pushes |
| Converting head to head to line at a fixed rate | On three illustrative spreads, one line fitted head to head prices from $1.36 to $1.61 | Convert per game, and treat it as an estimate |
When a line bet is the wrong choice
- Your view is only that your team wins. At -12.5, every win by 1 to 12 loses the bet, so the head to head prices that view directly.
- The number has moved past the one you rated. A line that has gone from -12.5 to -14.5 asks for two more points, so price it again before you bet.
- You do not know whether overtime or golden point counts. On a close line, extra time alone can flip the result, as in the -3.5 basketball case.
Different numbers at different bookmakers
Bookmakers can differ on the number as well as the price. With illustrative markets on one game, Bookmaker A has Team A -12.5 at $1.88, Bookmaker B has -11.5 at $1.83 and Bookmaker C has -13.5 at $1.97. A Team A win by exactly 12 wins only at Bookmaker B, and a win by exactly 13 wins at A and B but not C. So the best bet depends on the margin you expect, not on the highest price alone. Online, line markets close at the start, because the Interactive Gambling Act 2001 lets an Australian provider accept an online sports bet only before the event begins (s 10B and s 8A(3)).
On B337's Terminal, line markets sit beside the head to head and totals for each game, each bookmaker in its own column, with the best available price on each selection picked out. It draws on 40+ bookmakers across racing and sports, and not every bookmaker prices every game. Each price is refreshed on a repeating cycle, not tick by tick, so check both the number and the price with your bookmaker before you bet. A free account opens a limited view of the Terminal with live odds.
Risk: Betting involves risk. A better number or price improves what a winning line bet is worth, but a bet at even money still loses roughly half the time, and a line can move before your bet is accepted. See responsible gambling for limits and support.