Half Point Betting Tool
Weigh the cost and value of buying half a point on a spread against the added juice.
How to Use This Calculator
- Enter the point spread as it currently stands
- Enter the odds at that current spread, in American format (for instance, -110)
- Enter the odds you would face after buying a half point (for instance, -120)
- The tool then shows the cost in implied probability and whether buying the half point is worthwhile
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 it mean to buy a half point?
Buying a half point means paying additional juice (less favourable odds) to shift the spread 0.5 points your way. Moving from -3 to -2.5, for example, removes the prospect of a push on a margin of exactly 3 points.
Which are the key numbers in NFL betting?
Key numbers are the margins of victory that recur most often. In the NFL, 3 reigns supreme (~15% of games), trailed by 7 (~10%), then 1 (~6%), and 10 (~5%). Shifting away from these figures generally carries more value.
Is buying a half point usually a good move?
That turns on the number involved. Buying off 3 is almost always justified at standard prices, because roughly 15% of games land on 3. Buying off numbers that are not key seldom repays the extra outlay.
Does the same logic apply to the NBA?
NBA margins of victory spread more evenly, so no single figure carries the weight that 3 does in the NFL. The key NBA numbers are far less pronounced, which renders half-point purchases generally less valuable.