Buying Points: When It Makes Sense
The math behind key numbers and when paying extra vig is actually +EV
10 min read
The Quick Answer
Buying points is usually -EV—you're paying extra vig for minimal benefit. But there are specific exceptions where the math works in your favor.
In the NFL, buying onto or off of 3 and 7 can be +EV because games land on these key numbers far more often than the vig cost suggests. In basketball and most other sports, buying points is almost always a bad deal.
What Does "Buying Points" Mean?
Buying points means paying additional vig to move the spread or total in your favor. Most sportsbooks charge 10 cents per half-point—so moving a spread from -7 to -6.5 changes your odds from -110 to -120.
Example: Chiefs -7 (-110)
Original Line
Chiefs -7 (-110)
Buy ½ point
Chiefs -6.5 (-120)
Buy 1 full point
Chiefs -6 (-130)
Why Buying Points is Usually -EV
The math is simple: you're paying for something that rarely matters. Half a point only matters when the game lands exactly on that number—and that happens maybe 2-3% of the time for non-key numbers.
The Bad Math
Let's say you buy from -4.5 to -4. Games land on exactly 4 about 2.5% of the time in the NFL.
Extra vig cost: 10 cents (-110 → -120)
This costs you about 2.7% of expected return
But the number hits only ~2.5% of the time
You're paying more than the benefit is worth. Classic -EV.
NFL Key Numbers: Where Buying Points Works
The NFL is unique because scoring is discrete (3s and 7s), creating "key numbers"—margins that games land on disproportionately often. The two most important:
3
Field Goal Margin
- ~15% of NFL games land on 3
- Buying onto/off 3 can be +EV
- Books charge 25-30 cents to cross 3
7
Touchdown Margin
- ~9% of NFL games land on 7
- Second-most impactful key number
- Books charge 15-20 cents to cross 7
NFL Margin of Victory Frequency
| Margin | Frequency | Key Number? | Worth Buying? |
|---|---|---|---|
| 3 | ~15% | Primary | Often yes |
| 7 | ~9% | Primary | Sometimes |
| 6 | ~5% | Secondary | Rarely |
| 10 | ~6% | Secondary | Rarely |
| 14 | ~5% | Secondary | Rarely |
| 1, 2, 4, 5, 8, 9... | 2-4% each | No | No |
When Buying Points is +EV
- NFL: Buying from -3.5 to -3
You avoid pushing on exactly 3 (which happens ~15% of the time). If the cost is reasonable, this is often +EV.
- NFL: Buying from +2.5 to +3
You gain pushes on exactly 3 instead of losses. Same math—15% matters.
- NFL: Buying onto or off 7
At 9% frequency, this can be worth it if the vig cost is reasonable (15 cents or less).
- Teaser legs through key numbers
Teasers move you 6+ points. If your teaser crosses both 3 and 7, that's where value hides.
When Buying Points is -EV
- Non-key numbers in NFL
Moving from -4.5 to -4 or -5.5 to -5 isn't worth the vig. These numbers hit 2-3% of the time.
- NBA betting (almost always)
No true key numbers in basketball. Scoring is too continuous. Don't buy points.
- MLB run lines
Most games are decided by 1-2 runs, but the half-run doesn't justify the cost.
- College football (mostly)
Larger margins, more variance. Key numbers matter less than NFL.
- Buying multiple points
Each additional half-point has diminishing returns. The second half-point is worth less than the first.
Doing the Math: Is This Buy +EV?
Example Calculation
Scenario: You want to bet Chiefs -3 instead of -3.5. The book charges 25 cents to cross 3 (so -3 costs -135 vs -3.5 at -110).
Step 1: Calculate vig cost
At -110: You win $90.91 on $100 bet (47.6% BE)
At -135: You win $74.07 on $100 bet (57.4% BE)
Extra cost: ~2.8% of expected return
Step 2: Calculate benefit
Exactly 3 happens ~15% of the time
On -3.5, you lose all these (vs push on -3)
Push saves you ~7.5% of your bets (half of 15%)
Result: 7.5% benefit > 2.8% cost = +EV
This is why buying through 3 is often worth it in the NFL.
Find +EV Bets Without Guessing Key Numbers
We identify mathematically profitable bets daily—including when alternate lines and point purchases offer real value. Stop overpaying for points that don't matter.
The Bottom Line
Default position: don't buy points. Most point purchases are -EV because you're paying more than the mathematical benefit.
The exceptions: NFL key numbers (3 and 7) hit often enough that buying onto or off them can be worth the extra vig—if the price is right.
Do the math every time. Compare the cost of buying to the frequency of the number. If the number doesn't hit often enough to justify the vig, take the original line.
Frequently Asked Questions
What does buying points mean in sports betting?
Buying points means paying extra vig to move the spread or total in your favor. For example, instead of taking a team at -7 (-110), you might buy half a point to get -6.5 at -120. You're paying 10 cents more in vig for a more favorable line.
Is buying points ever worth it?
Buying points is worth it when the extra vig is less than the added value of the new line—specifically when crossing key numbers. In the NFL, buying onto or off of 3 and 7 can be +EV because games land on these numbers much more frequently than the vig suggests.
What are key numbers in NFL betting?
Key numbers are margins of victory that occur most frequently. In the NFL, 3 and 7 are the primary key numbers (field goal and touchdown margins). About 15% of games land on 3 and 9% on 7. Secondary key numbers are 6, 10, and 14.
Should I buy points in NBA betting?
Rarely. Unlike the NFL, NBA games don't cluster around specific margins of victory. There are no true key numbers because scoring is continuous and games end on various margins. The extra vig for buying points in basketball is almost always -EV.
How much does buying points typically cost?
Standard cost is 10 cents per half-point (e.g., -110 becomes -120). However, crossing key numbers in football costs more—buying through 3 typically costs 25-30 cents, and through 7 costs 15-20 cents. These costs vary by sportsbook.