NBA line betting puts a points start on the final score. The favourite gives points, the outsider receives them, and the bet settles on the score once the start is applied. Team A at -5.5 has to win by 6 or more, and Team B at +5.5 pays if it wins or loses by 5 or fewer.
Both sides are priced close to even money. The bookmaker sets the number where it expects the two sides to be near a coin toss, and puts its margin in the prices. Points in the NBA come in ones, twos and threes, so every margin is possible, and one point either side of the number decides the bet. The markets around the line are set out in NBA betting from Australia, part of the wider guide to US sports betting from Australia.
How a -5.5 line settles
With illustrative prices of $1.92 on Team A -5.5 and $1.90 on Team B +5.5, and $30 on each side:
| Final score | Margin | Team A -5.5 at $1.92 | Team B +5.5 at $1.90 |
|---|---|---|---|
| Team A 114, Team B 108 | Team A by 6 | 114 - 5.5 = 108.5, ahead of 108: returns $57.60 | 108 + 5.5 = 113.5, behind 114: loses |
| Team A 113, Team B 108 | Team A by 5 | 113 - 5.5 = 107.5, behind 108: loses | 108 + 5.5 = 113.5, ahead of 113: returns $57.00 |
| Team A 101, Team B 109 | Team B by 8 | Loses | Returns $57.00 |
| 104-104 after 48 minutes, Team A wins 111-107 in overtime | Team A by 4 | 111 - 5.5 = 105.5, behind 107: loses | 107 + 5.5 = 112.5, ahead of 111: returns $57.00 |
Return = stake x price, so $30 x 1.92 = $57.60, a $27.60 profit. The two prices add up to 1 / 1.92 + 1 / 1.90 = 52.08% + 52.63% = 104.71%. Those two percentages are also the share of bets each side has to win to break even.
A whole-number line adds a third result. At -5, the 113-108 game lands exactly on the number, and the common rule type hands both stakes back. A half-point line such as -5.5 can never land on the number, which is why it always has a winning side.
Spread, handicap or points start: one NBA bet
The NBA line goes by four names. US coverage calls it the spread or point spread and quotes -110 on each side, which is $1.91 in decimal odds. Australian bookmakers call it the line, the handicap or the points start. NSW's Bookmaker Declared Betting Events Betting Rules use the term points start. Unless the two sides agree on something else when the bet is struck, the start is set on a half point, such as 5.5 (clause 5.1.3).
A team's record against the line is its ATS record, and a team whose score beats the other side's once the start is applied has covered. Lines work the same way across sports, and the general guide to line betting sets the NBA beside the AFL, NRL and soccer's handicaps.
Overtime and the NBA line
Under the common rule type, a line bet counts every overtime period, and NSW's default does the same: a points start is settled including any extra time unless agreed otherwise (clause 5.1.3). An NBA overtime period lasts five minutes under Rule 5 of the NBA's playing rules, and periods keep coming until the tie is broken.
That changes what a line asks once a game is level after 48 minutes. The margin is then 0, so the final margin is whatever overtime produces, from five minutes of play instead of 48:
| Line | Level after 48 minutes: the favourite covers if it | The outsider covers if it |
|---|---|---|
| -2.5 / +2.5 | Wins overtime by 3 or more | Wins overtime, or loses it by 1 or 2 |
| -5.5 / +5.5 | Wins overtime by 6 or more | Wins overtime, or loses it by up to 5 |
| -8.5 / +8.5 | Wins overtime by 9 or more | Wins overtime, or loses it by up to 8 |
A favourite at -8.5 has to win five minutes of overtime by more than the line expected it to win the whole 48 minutes by. So the bigger the line, the more a tied game after regulation leans towards the outsider's side of it. The 111-107 overtime game shows the same thing at -5.5: Team B +5.5 covered.
A market settled on regulation time would treat a level game as a margin of 0, which pays every plus line and loses every minus line. Does overtime count in NBA betting compares the two kinds of market.
How injury news moves an NBA line
A line is the market's estimate of the final margin, and team news can shift that estimate by several points. The NBA's injury rules (the 2025-26 edition, still the latest when checked in October 2026) want a status on each doubtful player by 5 pm local time on the eve of a game.
A game-day report is due by 1 pm. For teams on US Eastern time between November and mid-March, that game-day deadline is 5 am in Sydney. A starter ruled out in that window can move the line before most Australian punters are awake.
Your ticket keeps its number when the market moves. Take an illustrative game that opens at Team A -5.5 ($1.92) and Team B +5.5 ($1.90). Overnight, Team A's starting point guard is ruled out, and the line moves to Team A -2.5. Assume, for illustration, that final margins scatter around the market's line in a bell curve with a standard deviation of 12 points:
| Bet placed before the news | Chance of winning after the move | Return per $1 (chance x price) |
|---|---|---|
| Team A -5.5 at $1.92 | 40.1% | 0.401 x 1.92 = 0.770 |
| Team B +5.5 at $1.90 | 59.9% | 0.599 x 1.90 = 1.138 |
Team A -5.5 now needs the margin to beat 5.5 when the market's line is 2.5. That is a gap of 3 points, or 3 / 12 = 0.25 of a standard deviation, and a normal table puts 40.1% of results beyond it. On this model the Team A ticket is worth 23c less than its stake per $1, and the Team B ticket about 14c more.
Getting a better number than the final pre-game line, consistently, is the idea behind closing line value.
Risk: Betting involves risk. A bet that beats the moved line can still lose, and these chances come from an assumed scatter of results, not a measured one. Lines also move on money as well as news, and the move can go against you. See responsible gambling for limits and support.
Alternate lines and their prices
Some bookmakers also price the same game at other numbers. Every point you take your way shortens the price, and every point you give away lengthens it. Australian bookmakers sell it under names such as pick your own line, and US coverage calls moving the number your way buying points. With an illustrative ladder for Team A around a main line of -5.5, and the same 12-point bell curve centred on a 5.5-point margin:
| Team A line | Price | Implied chance (1 / price) | Model chance | Return per $1 on the model |
|---|---|---|---|---|
| -1.5 | $1.52 | 65.8% | 63.1% | 0.958 |
| -3.5 | $1.70 | 58.8% | 56.6% | 0.963 |
| -5.5 | $1.92 | 52.1% | 50.0% | 0.960 |
| -7.5 | $2.18 | 45.9% | 43.4% | 0.946 |
| -9.5 | $2.50 | 40.0% | 36.9% | 0.924 |
| -11.5 | $2.90 | 34.5% | 30.9% | 0.895 |
In this ladder the rungs near the main line cost about 4c per $1 on the model, and the cost climbs to about 10.5c by -11.5. Two checks work on any real ladder:
- The gap between two rungs is the price of the margins in between. -5.5 at 52.1% and -7.5 at 45.9% put a win by exactly 6 or 7 at 6.2%, margin included. On your own numbers, -5.5 is the better rung when your chance of a 6- or 7-point win is more than 2.18 / 1.92 - 1 = 13.5% of your chance of a win by 8 or more (the market's 6.2 / 45.9 is the same 13.5%), and -7.5 is better when it is less. Or compare your chance x price for each rung directly.
- Pair a rung with the other side at the same number. If Team B +7.5 is $1.62, the pair adds up to 1 / 2.18 + 1 / 1.62 = 107.6%, against 104.7% for the main line, so this rung carries the bigger margin.
Risk: Betting involves risk. A ladder rung at a bigger price is a longer shot, not better value, and the model chances here are an assumption. See responsible gambling for limits and support.
Converting an NBA line to a head to head price
A line and a head to head ask different questions, so converting one into the other needs one more input: how widely final margins scatter around the line. Assume a bell curve again, with a standard deviation you choose. Team A's chance of winning is then the part of the curve above a margin of 0. A game level after 48 minutes goes to overtime, which either team can win, so a tie is not a result of its own.
In a spreadsheet, NORM.S.DIST(5.5 / 12, TRUE) = 0.677 for a fair -5.5 line and a standard deviation of 12.
| Fair line | Chance Team A wins, standard deviation 12 | Fair head to head price (1 / chance) |
|---|---|---|
| -1.5 | 55.0% | $1.82 |
| -3.5 | 61.5% | $1.63 |
| -5.5 | 67.7% | $1.48 |
| -7.5 | 73.4% | $1.36 |
| -9.5 | 78.6% | $1.27 |
| -11.5 | 83.1% | $1.20 |
The standard deviation matters as much as the line. At -5.5, a standard deviation of 10 points gives 70.9% and $1.41, and one of 14 points gives 65.3% and $1.53. To measure it yourself, record the closing line and the final margin for every game over a season. Take each margin minus the margin the line expected, and find the standard deviation of those differences. Treat any conversion as an estimate.
NBA line betting mistakes, costed
| Mistake | Cost (illustrative prices) | Fix |
|---|---|---|
| Reading -5.5 as "win by 5" | A 5-point win loses $30 at -5.5, as in the 113-108 game | Round the start up to the next whole point: 6 |
| Taking the higher price on a worse number | On the 12-point model, -4.5 at $1.87 returns 0.533 x 1.87 = 0.997 per $1 and -5.5 at $1.92 returns 0.960, so on this model the lower price loses less per $1, about 0.3c against 4c | Compare the number before the price |
| Backing a big line without allowing for overtime | From level after 48 minutes, -8.5 needs a 9-point overtime win | Price the chance of a tied game into big lines |
| Betting before the game-day report on a doubtful player | A 3-point move against you cost about 23c per $1 in the injury example | Wait for the report, or price the risk in |
| Using one conversion rate for every game | A fair -5.5 line fits $1.41 to $1.53 on standard deviations of 10 to 14 points | Convert game by game, as an estimate |
When bookmakers post different NBA lines
One bookmaker's -5.5 can sit beside another's -4.5 or -6.5, so line up the numbers before you compare prices. B337's Terminal has a sports board, with the NBA among its leagues whenever bookmakers have markets up. It puts each bookmaker's head to head, line and total prices in its own column and picks out the best available price on each selection. Behind it are 40+ bookmakers across racing and sports, and not all of them price every game.
Prices are read on a repeating cycle rather than tick by tick, so a line can move at the bookmaker before the board shows it. Check the number, the price and the overtime rule in your bookmaker account before placing anything. A free account opens a limited view of the Terminal with live odds.
Risk: Betting involves risk. A better line improves what a winning bet is worth, but at close to even money a line bet still loses about half the time. See responsible gambling for limits and support.