Python Program to Calculate the Number of Days Between Two Dates

In this tutorial, you will write a Python program to calculate the number of days between two dates.

If you are new to Python, to understand this code, you should first check:

• How to get basic input and output in Python
• If and else conditional statements in Python
• While loop in python
• Python Lists

Simple Code

while True:
    try:
        print('Enter date in the format : dd/mm/yy')
        date1 = input('Enter the first date : ')
        date2 = input('Enter the second date : ')
        date_1 = date1.split('/')
        date_2 = date2.split('/')
        diff = (int(date_2[2]) * 365 + int(date_2[1]) * 30 + int(date_2[0])) - (int(date_1[2]) * 365 + int(date_1[1]) * 30 + int(date_1[0]))
        print('The number of days between' , date2 , 'and' , date1 , 'is' , diff ,'days.')
        break
    except:
        print('Follow the format and use digits only')

Output

Enter date in the format : dd/mm/yy
Enter the first date :  20/10/2010
Enter the second date :  20/10/2011
The number of days between 20/10/2011 and 20/10/2010 is 365 days.

Code with explanation

#program will run until it is executed successfully!
while True:
    #This try block will be executed first and if the user enter the date in the right format, the result will be printed and program will end successfully
    #But if the user enter input in wrong formate, program will throw an error and will run again
    try:
        #take input from the user
        print('Enter date in the format : dd/mm/yy')
        #get the first date
        date1 = input('Enter the first date : ')
        #get the second date
        date2 = input('Enter the second date : ')
        
        #split the entered date into date, month and year by using .split() method
        #this split method will split the string into a list of number such as, 01/05/2010 will be converted to list ['01', '05', '2010']
        date_1 = date1.split('/')
        date_2 = date2.split('/')
        print(date_2)
        
        #calculating the difference between two dates by subtracting date 2 from date 1
        diff = (int(date_2[2]) * 365 + int(date_2[1]) * 30 + int(date_2[0])) - (int(date_1[2]) * 365 + int(date_1[1]) * 30 + int(date_1[0]))
        print('The number of days between' , date2 , 'and' , date1 , 'is' , diff ,'days.')
        #this break command will end the program if it is executed successfully.
        break
    #But in some cases, the user may enter some alphabet or any other character. Then this error will be displayed and loop will run the program again
    except:
        print('Invalid Entry. Follow the format dd/mm/yy and use digits only.')

Output

Enter date in the format : dd/mm/yy
Enter the first date :  20-01-10
Enter the second date :  20-01-11
Invalid Entry. Follow the format dd/mm/yy and use digits only.t
Enter date in the format : dd/mm/yy
Enter the first date :  20/10/2010
Enter the second date :  20/10/2011
The number of days between 20/10/2011 and 20/10/2010 is 365 days.