How to calculate number of days between two given dates

python

timedelta

dateutil

pandas

byAnton Shumikhin·Nov 12, 2024

To find the days difference between two dates, employ Python's datetime.strptime to parse dates and subtract to fetch the timedelta. Use the .days attribute to obtain the day count.

from datetime import datetime

# Parse dates and calculate difference in days
# Believe me, this incantation works! 🧙‍♂️
difference = (datetime.strptime('2023-01-31', "%Y-%m-%d") - datetime.strptime('2023-01-01', "%Y-%m-%d")).days

print(difference)  # Printing truth since 1990 🖨️

This snippet nimbly computes the days interval for YYYY-MM-DD formatted strings.

timedelta essentials

Subtraction principle

The engine of Python's date calculations is straightforward subtraction:

timedelta_object = end_date - start_date

You get a timedelta object, with the .days property giving you the desired day count.

Shoutout to leap years and varied month lengths

Python's datetime takes into account leap years and different month lengths, ensuring your results are always on point — never skip a leap!

Crafting date objects

From class to objects

Deepen your prowess by creating custom date objects via the date class:

from datetime import date

# Classy move, turning date class into date objects!
start_date = date(2023, 1, 1)
end_date = date(2023, 1, 31)

Then, just subtract these objects to get the same result as with datetime.

More than basic arithmetic? datetime.

Multi-level operations

From basic to advanced, the datetime library opens doors to intricate date arithmetic:

Add or subtract days with timedelta(days=n)
Get weeks, hours, minutes, and even microseconds by arguing with timedelta (and winning!)
Work on timezone-aware datetime objects instead of date, if global timestamps are your game

Pro tips for time travelers

Dealing with rogue date formats

Have other date formats in your lair? Coerce strptime to slay those dragons.

Spotting potential pitfalls

Get out of the pit by catching common trapdoors:

Playing with both naive and aware datetime objects in the same sandbox
Misrepresenting month (%m) and minute (%M) format codes — a classic comedian mix-up!

If there are stones, we'll cover those, too!

Time zones got you dizzy? Adjust for them.

When orchestrating global applications, become time zone savvy:

from datetime import datetime, timezone, timedelta

# Timezone-aware datetime objects — because the world doesn't spin around UTC
start_date = datetime(2023, 1, 1, tzinfo=timezone.utc)
end_date = datetime(2023, 1, 31, tzinfo=timezone.utc)

# No time(just day!) difference
difference = (end_date - start_date).days