Python strftime directive %U

Week of the year, Sunday as the first day (00–53). Days before the first Sunday are week 0.

In Python

from datetime import datetime
dt = datetime(2026, 6, 18, 13, 45, 30)
dt.strftime("%U")
# => "24"

Parsing with strptime

Parses a week number; needs a weekday to resolve a date. See strptime.dev for the parsing side.

Try %U in the live tester →

Other Week & ISO directives