Python: Numbers, Dates & Times

strftime & strptime Format Codes

Quick reference for all Python datetime format directives with examples and common patterns.

Date Codes

from datetime import datetime
dt = datetime(2026, 3, 25, 14, 30, 45)

# Date codes
dt.strftime("%Y")  # "2026"      (4-digit year)
dt.strftime("%y")  # "26"        (2-digit year)
dt.strftime("%m")  # "03"        (zero-padded month)
dt.strftime("%-m") # "3"         (no padding, Linux/macOS)
dt.strftime("%d")  # "25"        (zero-padded day)
dt.strftime("%-d") # "25"        (no padding, Linux/macOS)
dt.strftime("%B")  # "March"     (full month name)
dt.strftime("%b")  # "Mar"       (abbreviated month)
dt.strftime("%A")  # "Wednesday" (full weekday)
dt.strftime("%a")  # "Wed"       (abbreviated weekday)
dt.strftime("%j")  # "084"       (day of year, zero-padded)
dt.strftime("%U")  # "12"        (week number, Sunday start)
dt.strftime("%W")  # "12"        (week number, Monday start)

Time Codes

# Time codes
dt.strftime("%H")  # "14"   (24-hour, zero-padded)
dt.strftime("%I")  # "02"   (12-hour, zero-padded)
dt.strftime("%M")  # "30"   (minutes, zero-padded)
dt.strftime("%S")  # "45"   (seconds, zero-padded)
dt.strftime("%p")  # "PM"   (AM/PM)
dt.strftime("%f")  # "000000" (microseconds, zero-padded)
dt.strftime("%Z")  # ""     (timezone name, empty if naive)
dt.strftime("%z")  # ""     (UTC offset, empty if naive)

Common Format Patterns

# Common patterns
dt.strftime("%Y-%m-%d")              # "2026-03-25"  (ISO date)
dt.strftime("%m/%d/%Y")              # "03/25/2026"  (US date)
dt.strftime("%B %d, %Y")            # "March 25, 2026"
dt.strftime("%I:%M %p")             # "02:30 PM"
dt.strftime("%H:%M:%S")             # "14:30:45"    (24-hour time)
dt.strftime("%Y-%m-%dT%H:%M:%S")    # "2026-03-25T14:30:45" (ISO 8601)
dt.strftime("%A, %B %d, %Y %I:%M %p")  # "Wednesday, March 25, 2026 02:30 PM"

# Parsing strings back to datetime
datetime.strptime("2026-03-25", "%Y-%m-%d")
datetime.strptime("03/25/2026 02:30 PM", "%m/%d/%Y %I:%M %p")
datetime.fromisoformat("2026-03-25T14:30:45")  # Python 3.7+