# Python program to find number of days between two given dates

• Difficulty Level : Medium
• Last Updated : 30 Dec, 2022

Given two dates, Write a Python program to find the total number of days between them.

Examples:

```Input : dt1 = 13/12/2018, dt2 = 25/2/2019
Output : 74 days

Input : dt1 = 01/01/2004, dt2 = 01/01/2005
Output : 366 days ```

Naive Approach: One Naive Solution is to start from dt1 and keep counting days till dt2 is reached. This solution requires more than O(1) time.

A Better and Simple solution is to count the total number of days before dt1 from i.e., total days from 00/00/0000 to dt1, then count the total number of days before dt2. Finally, return the difference between the two counts.

## Python3

 `# Python3 program two find number of` `# days between two given dates`   `# A date has day 'd', month 'm' and year 'y'`     `class` `Date:` `    ``def` `__init__(``self``, d, m, y):` `        ``self``.d ``=` `d` `        ``self``.m ``=` `m` `        ``self``.y ``=` `y`     `# To store number of days in all months from` `# January to Dec.` `monthDays ``=` `[``31``, ``28``, ``31``, ``30``, ``31``, ``30``,` `             ``31``, ``31``, ``30``, ``31``, ``30``, ``31``]`   `# This function counts number of leap years` `# before the given date`     `def` `countLeapYears(d):`   `    ``years ``=` `d.y`   `    ``# Check if the current year needs to be considered` `    ``# for the count of leap years or not` `    ``if` `(d.m <``=` `2``):` `        ``years ``-``=` `1`   `    ``# An year is a leap year if it is a multiple of 4,` `    ``# multiple of 400 and not a multiple of 100.` `    ``return` `int``(years ``/` `4``) ``-` `int``(years ``/` `100``) ``+` `int``(years ``/` `400``)`     `# This function returns number of days between two` `# given dates` `def` `getDifference(dt1, dt2):`   `    ``# COUNT TOTAL NUMBER OF DAYS BEFORE FIRST DATE 'dt1'`   `    ``# initialize count using years and day` `    ``n1 ``=` `dt1.y ``*` `365` `+` `dt1.d`   `    ``# Add days for months in given date` `    ``for` `i ``in` `range``(``0``, dt1.m ``-` `1``):` `        ``n1 ``+``=` `monthDays[i]`   `    ``# Since every leap year is of 366 days,` `    ``# Add a day for every leap year` `    ``n1 ``+``=` `countLeapYears(dt1)`   `    ``# SIMILARLY, COUNT TOTAL NUMBER OF DAYS BEFORE 'dt2'`   `    ``n2 ``=` `dt2.y ``*` `365` `+` `dt2.d` `    ``for` `i ``in` `range``(``0``, dt2.m ``-` `1``):` `        ``n2 ``+``=` `monthDays[i]` `    ``n2 ``+``=` `countLeapYears(dt2)`   `    ``# return difference between two counts` `    ``return` `(n2 ``-` `n1)`     `# Driver program` `dt1 ``=` `Date(``13``, ``12``, ``2018``)` `dt2 ``=` `Date(``25``, ``2``, ``2019``)`   `print``(getDifference(dt1, dt2), ``"days"``)`

Output:

`74 days`

Time Complexity: O(1)
Auxiliary Space: O(1)

Using Python datetime module:

Python comes with an inbuilt datetime module that helps us to solve various datetime related problems. In order to find the difference between two dates we simply input the two dates with date type and subtract them, which in turn provides us the number of days between the two dates.

## Python3

 `# Python3 program to find number of days` `# between two given dates` `from` `datetime ``import` `date`   `def` `numOfDays(date1, date2):` `    ``return` `(date2``-``date1).days` `    `  `# Driver program` `date1 ``=` `date(``2018``, ``12``, ``13``)` `date2 ``=` `date(``2019``, ``2``, ``25``)` `print``(numOfDays(date1, date2), ``"days"``)`

Time Complexity: O(1)
Auxiliary Space: O(1)

One approach is to use the dateutil library, which provides a more convenient and flexible way of handling dates and times in Python. To install dateutil, you can use the following command:

`pip install python-dateutil`

To find the number of days between two dates using dateutil, you can use the rdelta function from the relativedelta module, as shown in the example below:

## Python3

 `from` `dateutil ``import` `relativedelta` `from` `datetime ``import` `datetime`   `# Parse the dates from strings into datetime objects` `date1 ``=` `datetime.strptime(``"13/10/2018"``, ``"%d/%m/%Y"``)` `date2 ``=` `datetime.strptime(``"25/12/2018"``, ``"%d/%m/%Y"``)`   `# Calculate the difference between the two dates` `difference ``=` `relativedelta.relativedelta(date2, date1)` `# Print the number of days between the two dates` `print``(difference.months,``"months"``,difference.days, ``"days"``)`   `#This code is contributed by Edula Vinay Kumar Reddy`

Time Complexity: O(1)
Auxiliary Space: O(1)

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