Sportsbooks let you buy or sell half points on spreads and totals. Moving a line from -3 to -2.5 costs extra juice. But is it worth the price? The answer depends on the specific number — and most bettors get it wrong.
What is Buying Points?
Buying points means paying worse odds to move the spread or total in your favor. Selling points means accepting better odds by moving the line against you.
Example
| Line | Odds |
|---|---|
| Chiefs -3 (standard) | -110 |
| Chiefs -2.5 (bought half point) | -125 |
| Chiefs -3.5 (sold half point) | +100 |
Buying the half point from -3 to -2.5 costs you the difference between -110 and -125. That’s about 3% in implied probability. Is that half point worth 3%?
Try the half-point-calculator→
Key Numbers in Football
Not all half points are created equal. In football, certain numbers are dramatically more valuable than others because of common margins of victory:
| Margin of Victory | NFL Frequency |
|---|---|
| 3 points | ~15% |
| 7 points | ~9% |
| 6 points | ~5% |
| 1 point | ~4.5% |
| 10 points | ~4% |
3 is king. Roughly 15% of NFL games land exactly on a 3-point margin. Moving through the 3 (from -3 to -2.5 or from +2.5 to +3) captures a massive amount of probability.
7 is second. About 9% of games land on exactly 7. Moving through 7 is also highly valuable.
Other numbers (4, 5, 8, 9) are far less important. Games rarely land exactly on these margins, so buying through them is usually overpriced.
When Buying is Worth It
Buying Through 3 (NFL)
Moving from -3 to -2.5 avoids a push about 15% of the time and converts roughly half of those pushes into wins. If the sportsbook charges -125 to buy the half point (about 3-4% in probability terms), you’re paying 3-4% for ~7.5% of value. That’s a good deal.
Buying Through 7 (NFL)
Same logic, smaller effect. Games land on 7 about 9% of the time. At the right price, buying through 7 is +EV.
Buying Through 0 (Any Sport)
Moving from -1 to +0.5 (pick’em territory) or from +0.5 to +1.5 buys through the most common margin in basketball and hockey. Worth evaluating case by case.
When Buying is a Trap
Non-Key Numbers
Buying from -4 to -3.5 in football? Games land on exactly 4 about 4% of the time. You’re paying similar juice for far less probability improvement. The math rarely works.
Stacking Purchases
Some bettors buy 2 or 3 points on a spread. Each additional half point costs more juice, and the value drops rapidly after the first key number. By the time you’ve moved a line from -7 to -4.5, you’ve paid an enormous premium for a line that probably isn’t +EV anymore.
Basketball and Baseball Spreads
Basketball and baseball have much more variance in final margins. Key numbers exist (certain margins are slightly more common), but the effect is much weaker than football’s 3 and 7. The cost of buying points in these sports is usually not worth it.
Selling Points: The Reverse Play
Selling points works the opposite way. You move the line against yourself for better odds.
Example: Moving from +3 to +2.5 might improve your odds from -110 to +100. You’re giving up coverage on the 3 in exchange for reduced vig.
If the extra probability of landing on 3 is worth less than the juice saved, selling is the right play. This happens more often than you’d think on non-key numbers.
How to Evaluate the Cost
The half point calculator converts the cost of buying points into probability terms:
Calculate implied probability at the standard line
Calculate implied probability at the bought line
The difference is what you’re paying in probability terms
Compare to the actual probability of the game landing on that number
If you’re paying 3% for a number that hits 7.5% of the time, buy. If you’re paying 3% for a number that hits 2% of the time, don’t.
Key Takeaways
Buying through 3 and 7 in the NFL is often worth the cost
Non-key numbers (4, 5, 8, 9) are almost never worth buying through
The calculator converts the cost into probability terms so you can compare apples to apples
Selling points on non-key numbers can reduce your vig for minimal downside
Don’t stack point purchases — value drops rapidly after the first key number
