What is Key Numbers?
The most common margins of victory in a sport — crossing them with a spread or hook adds disproportionate value.
In NFL, the most frequent margins are 3, 7, 6 and 10. Moving a spread from −3 to −2.5 takes a chunk of ties off the table and adds 4–6% to implied probability. Sportsbooks know which numbers matter and rarely move past them by accident — that is why a half-point either way at a key number costs more vig than at a non-key number.
Related terms
A handicap a sportsbook adds to the underdog (or subtracts from the favorite) to make a moneyline mismatch into a roughly 50/50 market.
Comparing prices at multiple sportsbooks to bet the best available number on every play.
Betting only when your estimated win probability is higher than the bookmaker's implied probability.
See key numbers applied to a real slate
NotaSportsGuru runs the math behind every published leg — Parlay of the Day, player props, match lines — with the model’s expected value and edge on every line.