Key Numbers

Key numbers are the margins of victory that occur most frequently in a given sport, making the point spreads around those numbers particularly important for bettors. In NFL football, for example, the most common final margins are 3 and 7, because games are often decided by a field goal or a touchdown. A bettor who understands key numbers recognizes that the difference between getting a spread of -2.5 versus -3.5 is far more consequential than the difference between -4.5 and -5.5, because many more games are decided by exactly 3 points than by exactly 5 points.

Key numbers exist because the scoring structures of each sport create natural clustering in final margins. In football, the 3-point field goal and 7-point touchdown (with extra point) cause results to pile up at those margins and their multiples. In basketball, where individual possessions are worth 2 or 3 points and scoring is high, key numbers are less pronounced but still present. Bettors who are aware of these patterns can make smarter decisions about when to buy or sell half points, when a line move represents real value, and when a seemingly small difference in spread is actually significant.

Example

An NFL game has the home team favored by 3 points. Sportsbook A offers -3 (-110), while Sportsbook B has moved to -3.5 (-105). Although -3.5 at -105 appears cheaper in terms of juice, the bettor who takes -3 at -110 lands on the key number. Historical data shows that roughly 15% of NFL games are decided by exactly 3 points. At -3, those games result in a push (returned stake) rather than a loss. That single half point around the key number of 3 is worth far more than a half point in a range like 5 to 5.5, where far fewer games land on that exact margin.

Key Points

• Sport-specific: Key numbers vary by sport. In the NFL, 3 and 7 dominate. In the NBA, key numbers are less impactful because of higher and more variable scoring. Each sport has its own distribution of final margins.
• Half points matter most around key numbers: Buying a half point to move from -3.5 to -3 in football is significantly more valuable than moving from -6.5 to -6, because more games land on 3 than on 6.
• Inform line shopping priorities: When the spread sits on or near a key number, even small differences between sportsbooks become critical, making line shopping especially important.
• Affect teaser strategy: In football, teasers that cross through key numbers of 3 and 7 are considered the most valuable because they capture the highest concentration of final margins.
• Not static: While the core key numbers in football have remained stable for decades, rule changes and evolving offensive strategies can gradually shift the distribution of scoring margins over time.