Betting Calculators
Half Point Calculator
Calculate the cost and value of buying half points on point spreads. Determine if paying extra juice to move off a key number is worth it.
How to Use This Calculator
- Enter the current point spread
- Enter the odds at the current spread (in American format, e.g., -110)
- Enter the odds if you buy a half point (e.g., -120)
- View the cost in implied probability and whether it’s worth buying the half point
Formula
Implied Probability from American Odds:
- Negative: |Odds| / (|Odds| + 100) x 100
- Positive: 100 / (Odds + 100) x 100
Cost of Half Point = Implied Prob (Half Point Odds) - Implied Prob (Current Odds)
Worth buying if Cost < Probability of game landing on the number
Frequently Asked Questions
What does buying a half point mean?
Buying a half point means paying extra juice (worse odds) to move the spread by 0.5 points in your favor. For example, moving from -3 to -2.5 eliminates the chance of a push on exactly 3 points.
What are key numbers in NFL betting?
Key numbers are the most common margins of victory. In the NFL, 3 is the most important (~15% of games), followed by 7 (~10%), 1 (~6%), and 10 (~5%). Moving off these numbers is generally more valuable.
Is it usually worth buying a half point?
It depends on the number. Buying off 3 is almost always worth it at standard prices because games land on 3 about 15% of the time. Buying off non-key numbers is rarely worth the extra cost.
Does this work for NBA?
NBA margins of victory are more evenly distributed, so no single number is as important as 3 in the NFL. Key NBA numbers are less pronounced, making half-point purchases generally less valuable.