Half Point Betting Calculator
Cost and value of buying half a point on a spread.
How to Use This Calculator
- Input the current point spread
- Input the odds at the current spread (American format, e.g., -110)
- Input the odds if you buy a half point (e.g., -120)
- Read off the cost in implied probability and whether buying the half point pays off
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 shift the spread 0.5 points in your favor. Moving from -3 to -2.5, for instance, removes the push risk on exactly 3 points.
What are key numbers in NFL betting?
Key numbers are the most frequent margins of victory. In the NFL, 3 is the most significant (~15% of games), then 7 (~10%), 1 (~6%), and 10 (~5%). Crossing these numbers generally carries more value.
Is buying a half point usually worthwhile?
It hinges on the number. Buying off 3 is almost always justified at standard prices, since games land on 3 roughly 15% of the time. Buying off non-key numbers seldom justifies the added cost.
Does this apply to the NBA?
NBA victory margins spread more evenly, so no single number carries the weight that 3 does in the NFL. Key NBA numbers are less pronounced, which makes half-point purchases generally less valuable.