Half point calculator: what buying a half point is worth
A half point and buying points calculator: what moving onto or off a key number like 3 or 7 is worth, and the worst price worth paying for it, in football, basketball, hockey, baseball and soccer. Or compare two spreads at two books: which bet is worth more, and by how much.
Half point calculator
Example Our example: an NFL favorite at −3 (−110 both sides), bought to −2.5 at −125.
−3 → −2.5: worth it at −130 or better · at −125: Worth itBuying to −2.5 is worth it at −130 or betterthe price where −2.5 is worth the same as −3 at −110 · no-vig at −2.5: −119
Worth it. At −125 the half point costs less than it is worth: −$2.37 per $100 at −2.5, against −$4.16 at −3 −110. It is still a losing bet on the model; buying makes it lose less, not a winner.
| −3 −110 | −2.5 −125 | Change | |
|---|---|---|---|
| Win | 45.8% | 54.2% | +8.5% |
| Push | 8.5% | 0.0% | −8.5% |
| Loss | 45.8% | 45.8% | 0.0% |
| EV per $100 | −$4.16 | −$2.37 | +$1.79 |
| No-vig price | +100 | −119 |
Buying a half point from −3 to −2.5 adds 8.5% to your win chance, across a key number:
- 8.5% of games turn from a push into a win — games where your side wins by exactly 3
Show the numbers
| Your side’s margin | Chance | At −3 | At −2.5 |
|---|---|---|---|
| −10 | 2.3% | loss | loss |
| −9 | 1.1% | loss | loss |
| −8 | 1.9% | loss | loss |
| −7 | 4.0% | loss | loss |
| −6 | 2.9% | loss | loss |
| −5 | 2.0% | loss | loss |
| −4 | 2.8% | loss | loss |
| −3 | 7.6% | loss | loss |
| −2 | 2.0% | loss | loss |
| −1 | 2.2% | loss | loss |
| 0 | 0.1% | loss | loss |
| +1 | 2.2% | loss | loss |
| +2 | 2.1% | loss | loss |
| +3 | 8.5% | push | win |
| +4 | 3.2% | win | win |
| +5 | 2.4% | win | win |
| +6 | 3.6% | win | win |
| +7 | 5.2% | win | win |
| +8 | 2.5% | win | win |
| +9 | 1.5% | win | win |
| +10 | 3.2% | win | win |
| +11 | 1.6% | win | win |
| +12 | 1.3% | win | win |
| +13 | 1.4% | win | win |
| +14 | 2.7% | win | win |
| +15 | 1.2% | win | win |
Every half point within 3 points
Against −3 at its price: the chance of each result on every number, its no-vig price, and the price it is worth paying to move there. Key numbers (−6, −3) are marked.
| Spread | Lands | Win | Vs now | No-vig | Worth it at |
|---|---|---|---|---|---|
| −6key | 3.6% | 36.5% | −9.2% | +164 | +153 |
| −5.5 | — | 40.1% | −5.6% | +149 | +139 |
| −5 | 2.4% | 40.1% | −5.6% | +143 | +133 |
| −4.5 | — | 42.5% | −3.2% | +135 | +126 |
| −4 | 3.2% | 42.5% | −3.2% | +128 | +118 |
| −3.5 | — | 45.8% | 0.0% | +119 | +110 |
| −3key yours | 8.5% | 45.8% | — | +100 | your bet |
| −2.5 new | — | 54.2% | +8.5% | −119 | −130 |
| −2 | 2.1% | 54.2% | +8.5% | −124 | −137 |
| −1.5 | — | 56.4% | +10.6% | −129 | −142 |
| −1 | 2.2% | 56.4% | +10.6% | −136 | −151 |
| −0.5 | — | 58.6% | +12.8% | −141 | −157 |
| PK | 0.1% | 58.6% | +12.8% | −142 | −157 |
“Lands”: the chance the result is exactly that number, a push there (half numbers never push). “Worth it at”: the worst price on that number that is still worth as much as your bet.
Games on key numbers right now
Spreads and totals on the board that sit on or a half point off a key number, with the board’s best price and what the half point is worth there. Load one into the calculator above, or compare two books on different numbers.
Games on key numbers load here in your browser.
The math
EV per $1 = win × (decimal − 1) − loss · a push returns the stake
−3 at −110: 45.8% × 0.909 − 45.8% = −$4.16 per $100 (8.5% push)
−2.5 at −125: 54.2% × 0.800 − 45.8% = −$2.37 per $100 (no push)
worth it at: 54.2% × (d − 1) − 45.8% = −4.16% → d = 1.767 → −130
In the example both sides of −3 are −110, so with the vig removed the favorite covers half the time when the game does not land on 3. The model then puts 8.5% of games exactly on 3, leaving 45.8% wins and 45.8% losses. Off 3, at −2.5, every one of those pushes is a win: 54.2%. Paying −125 for that is a good trade, since the half point is worth anything up to about −130. It is still not a good bet: the no-vig price on −2.5 is about −119, so at −125 the bet loses less, but it still loses.
Key numbers
Football scores come in threes and sevens, so some final margins come up far more often than their neighbors. Those are the key numbers, and a half point onto or off one is worth much more than a half point anywhere else. In the model the NFL’s are 3, 7, 6, 10 and 14 (3 most of all), college football’s 3 and 7, then 10, 14, 17, 21 and on through the 40s, and the NFL’s totals 37, 41, 43, 44, 47 and 51. College football totals have many milder ones (30, 31, 33, 34, 37, 38, 41, 44, 45, 48, 51 and 55), none anywhere near as strong as a side’s 3 or 7: a college total is often next to one, but a half point there is worth far less than one onto 3 or 7. Basketball margins have no key numbers in the model: every half point is worth about the same, and seldom the 10 or 20 cents a book asks for it (in college basketball and the WNBA a one-point game is rarer than its neighbors, so a half point through 1 is worth even less).
Hockey and baseball have key totals instead: the odd ones. About 7 in 10 NHL totals are odd: one- and three-goal wins in regulation make nearly half of them odd, and every game that goes to overtime or a shootout (level, so even, after 60 minutes) gains one goal and ends odd. A home team that leads skips the bottom of the ninth, so 59% of MLB totals are odd. Bought from 5.5 to 5, an NHL over turns every 5-goal game from a loss into a push, and in the model about 23% of totals closing at 5.5 land on exactly 5. On the run line the key is the one-run game, and it depends on who is home. In soccer the key is the draw: between a quarter and a third of matches at a handicap of 0 or −0.5 end level, so −0.5 to 0 (draw no bet) is the most valuable half goal there is, and the most expensive.
When buying points is a bad bet
A bought half point is only as good as its price. Books charge for every half point, often the same on a dead number as on 3. The ladder shows where that price is worth paying and where it is not: off a number few games land on, the worth-it price is barely worse than the price you already have. And a better number never makes a bad side good. If the bet is not worth taking at the no-vig price, it is not worth taking with half a point bought on it either. Check the side first with the EV calculator, and shop the number across books before paying for one: another book may already hang −2.5, which the list above shows when a ranked book does.
Comparing two spreads
Books often hang different numbers on the same side: −7 at +100 at one, −6.5 at −120 at another. Switch the calculator to Compare two spreads (it takes totals too) and enter both. The other side’s price at either number removes the vig, the model is fitted once, and both bets are valued off it with pushes kept: win, push and loss for each, EV per $100, the difference, and the price the worse bet would need to match the better one. The numbers can be up to 3 points apart, and either one can be the better number.
The better number is not always the better bet. In our example, −6.5 turns the 5.4% of games your side wins by exactly 7 from pushes into wins, but paying −120 instead of +100 costs more than that is worth: −7 at +100 is better by $2.99 per $100, and −6.5 would need −112 or better to match it. Both are still losing bets on the model, so the better one loses less; it does not win. When two ranked books on the board post different numbers on one side, the list above offers to compare them.
How it works
The calculator removes the vig from your two prices (the power method, as the no-vig calculator), fits vigged’s model of final margins and totals to that chance, and reads win, push and loss at your number and every number in reach of it. The model is an approximation: a smooth curve around the market’s own expectation with extra weight where finals cluster, the same one the middles finder uses for its hit rates. It is not a lookup of past results, and it is least sure far from the market’s number, so the calculator moves a number only as far as the model was checked against history: 3 points in football and basketball, 2 goals on an NHL total (past one it says approximate), the puck line from 1.5 toward the moneyline, 1.5 runs in baseball, and a goal in soccer. Until the board loads, the calculator shows our own example: an NFL favorite at −3 (−110 both sides), bought to −2.5 at −125.
The model against history
Every league the calculator covers was backtested the way the calculator works: each game’s closing line (its no-vig price where the archive has one) fitted to the model, and the model’s chances scored against that game’s final score. Where history disagreed, the model was retuned and checked again on seasons it was not fitted to: college football’s keys now reach through the 40s, college basketball and the WNBA have their one-point hole, the NHL and MLB their odd totals and MLB its home-team one-run wins, and soccer has a model of its own. The NFL and NBA models held up and were kept. Below, the model’s figure at a −110 / −110 close next to what happened. The full backtest, league by league, is on the half point backtest page.
| What was counted | Model | History (95% range) | Games |
|---|---|---|---|
| NFL | |||
| Games closing −3 that landed on exactly 3 | 8.5% | 9.2% (7.7–11.0) | 1,164 games, 1999–2026 |
| Games closing −3.5 that landed on exactly 3 | 8.4% | 9.8% (7.8–12.3) | 692 games, 1999–2026 |
| Games closing −7 that landed on exactly 7 | 5.4% | 6.8% (4.9–9.4) | 497 games, 1999–2026 |
| What the half point −3 → −2.5 is worth | 18.5¢ | 20.2¢ (16.7–24.7) | 1,164 games, 1999–2026 |
| College football | |||
| Games closing −3 that landed on exactly 3 | 6.8% | 6.0% (4.7–7.7) | 965 games, 2006–2025 |
| Games closing −7 that landed on exactly 7 | 6.0% | 5.9% (4.4–7.9) | 725 games, 2006–2025 |
| Games closing −7 that landed on exactly 9 | 0.9% | 0.8% (0.4–1.8) | 725 games, 2006–2025 |
| Totals closing 55 that landed on exactly 55 | 3.9% | 3.9% (2.4–6.2) | 411 games, 2006–2024 |
| MLB | |||
| Totals closing 7.5 that ended on exactly 7 runs | 11.1% | 12.1% (9.4–15.4) | 454 games, 2016 |
| Totals closing 7.5 that ended on exactly 8 runs | 7.6% | 9.5% (7.1–12.5) | 454 games, 2016 |
| Home favorites at −1.5 that won by exactly 1 run | 17.6% | 17.1% (15.3–19.0) | 1,584 games, 2016 |
| Away favorites at −1.5 that won by exactly 1 run | 12.0% | 12.9% (10.8–15.4) | 835 games, 2016 |
| Soccer (big five) | |||
| Handicap 0 (draw no bet) that pushed: a draw | 29.5% | 29.6% (26.1–33.5) | 587 games, 2023/24–2025/26 |
| Favorites at −0.5 whose match ended in a draw | 27.5% | 28.3% (25.6–31.2) | 992 games, 2023/24–2025/26 |
| Even-priced 2.5-goal totals that ended on exactly 2 goals | 25.2% | 25.0% (23.0–27.0) | 1,781 games, 2023/24–2025/26 |
History: closing (or near-closing) lines and final scores, overtime, shootouts and extra innings included (soccer after 90 minutes and stoppage time); nflverse’s NFL lines are its closing-time lines, not one named book’s. The model column is worked out live from the model the calculator uses, at a −110 / −110 close. The range is where history’s figure would fall 95 times in 100 by chance alone (for the half point’s value, in cents of break-even price, a resampling of the games): a model figure inside it is as close as these games can tell. College football’s keys were fitted on 2006–2025; fitted on 2006–14 alone, the same method matched 2015–25 on all 17 key numbers. MLB’s were fitted on 2014–19 (2016 included) and held on 2021–25; soccer’s on 2019/20–2022/23, and the rows here are later seasons of the big five only.
At 3 and 7 NFL games have landed a little more often than the model says, so half points there may be worth 1 to 3 cents more than the calculator shows. The NBA, WNBA, college basketball and NHL models were checked the same way (and the last three retuned), but on line archives licensed for research use only, so their figures are not published here; nor are MLB’s 2021–25 retail lines.
- NFL lines and scores: nflverse (Lee Sharpe) (CC BY 4.0; figures aggregated by vigged)
- College football lines and scores: cfbfastR-data / SportsDataverse (CC BY 4.0; figures aggregated by vigged), from CollegeFootballData.com; 2006–19 lines originally collected from Sportsbook Review.
- MLB 2016 closing lines: the pinnacle.data R package (GPL-3; figures aggregated by vigged).
- The information used here was obtained free of charge from and is copyrighted by Retrosheet. Interested parties may contact Retrosheet at www.retrosheet.org.
- Football results and odds: Football-Data (www.football-data.co.uk)
Related: a half point between two books can also make a middle, and a better price on the same number is worth money too, see worst line vs best line.
Frequently asked questions
Is buying a half point worth it?
Only at the right price. Off 3 in the NFL it often is: in vigged’s model about 8.5% of games on a 3-point spread land exactly on 3, and buying from −3 to −2.5 turns every one of those pushes into a win. At −110 on −3, buying to −2.5 is worth it at about −130 or better. On a number few games land on, the same half point is worth far less, and paying 20 cents for it is a bad trade.
What is a half point worth in the NFL?
It depends on the number it crosses. A half point onto or off 3 or 7 changes the result of many more games than one around 5 or 9, because so many NFL games are decided by exactly 3 or 7. The ladder in the calculator shows every half point within 3 points of your number, with how often the result lands on each one and the price each move is worth.
Which sports does the half point calculator work for?
The NFL and college football; the NBA, WNBA and college basketball; the NHL (totals, and the puck line from 1.5 toward the moneyline); MLB (totals, and the run line for the home or the away team); and soccer’s big five leagues, the Premier League, La Liga, Serie A, the Bundesliga and Ligue 1 (Asian handicaps on whole and half goals, and 2.5-goal totals, a goal either way). Each one moves a number only as far as its model was checked against history. Not MLS, Liga MX or the Champions League, and not soccer’s quarter lines.
Why does home or away matter on the MLB run line?
Because the home team bats last. When it leads after the top of the ninth the game is over, and a walk-off ends it the moment the winning run scores, so home teams win by exactly one run far more often than away teams: in 2016, 17.1% of home favorites at −1.5 won by exactly one run, against 12.9% of away favorites. That makes a home favorite’s −1.5 worth less, and buying it to −1 worth more, than the same numbers for an away team. The calculator asks which team you are on.
How is the break-even price worked out?
From the market itself. Both prices are de-vigged (power method) to get the chance your side covers, pushes left out. vigged’s key-number model is fitted to that chance, and gives win, push and loss at every nearby number. The break-even is the price on the new number whose expected value equals the bet you already have; a push returns the stake.
If buying the half point is worth it, is the bet a good bet?
Not necessarily. At −110 on −3, the bet loses about $4.16 per $100 on the model, and buying to −2.5 at −125 still loses about $2.37. Buying cuts the loss; it does not make a losing bet a winner. A bet is only +EV when its price beats the no-vig price on its own number, which the calculator also shows.
Can I sell points instead?
Yes. Pick a worse number, such as −3.5 from −3, and enter the better price the book gives you for it. Selling off 3 gives up every push on 3, so it needs a big price improvement: against −3 at −110, −3.5 is only worth it at about +110 or better.
How do I compare two spreads at different books?
Switch the calculator to Compare two spreads and enter each bet’s number and price (and its book, if you like). Both bets are valued on the same model, fitted to the market’s no-vig price with pushes kept, so you get the EV of each, the difference per $100 and over 100 bets, and the price the worse bet would need to match the better one. Our example: −7 at +100 at one book against −6.5 at −120 at another, with +7 at −120 on the other side. −6.5 is the better number, but on the model −7 at +100 is the better bet by $2.99 per $100, about $299 over 100 bets of $100, and −6.5 would need −112 or better to match it. Both still lose ($4.39 and $7.38 per $100): the better one loses less.
Where do the percentages come from? Is this historical data?
They come from vigged’s model of final margins and totals: a smooth curve around the market’s own expectation, with extra weight where finals cluster (football’s 3 and 7, hockey’s and baseball’s odd totals, the soccer draw) and less where they are rare (one-point games in college basketball and the WNBA). It is fitted to the market’s no-vig price, so it is an approximation, not a lookup of past results. It has been checked against them, though: closing lines and final scores in every league it covers, and retuned where history disagreed (college football, college basketball, the WNBA, the NHL, MLB and soccer). The table on this page puts the model’s figures next to history’s.
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