Rules that decide games
Periods, halftime and overtime
3 min
Basketball is played in timed blocks, with breaks, and a tie-breaker if needed. The exact structure depends on the league.
The structure
Most professional leagues play four quarters. US college basketball (NCAA) plays two halves instead. There is a longer halftime break in the middle, and shorter breaks between the other periods.
The exact length of each period changes by league — FIBA quarters are 10 minutes, NBA quarters are 12, NCAA halves are 20. The full breakdown lives in the Leagues & Formats track.
Overtime
If the score is tied at the end of regulation, the teams play a short overtime (OT) period. If it's still tied, they play another, and so on until one team leads when an OT ends. There is no limit on how many OTs a game can have.
Why the format matters
Period length sets the pace ceiling — more minutes means more possessions and higher totals. Knowing whether you're watching 4×10, 4×12, or 2×20 instantly tells you what a "normal" final score looks like, which is the foundation for reading any over/under line.