Pandas – Number of Months Between Two Dates

In this article, we are going to find the number of months between two dates in pandas using Python. 

Example 1:

We will take a dataframe and have two columns for the dates between which we want to get the difference. Use df.dates1-df.dates2 to find the difference between the two dates and then convert the result in the form of months. Convert into ‘int’ datatype else result will be in form of float.

Python3

# Importing required libraries
import pandas as pd
import numpy as np
import datetime

# Making a dataframe which will have two
# columns two store different dates
df = pd.DataFrame({'dates1': np.array(
  [datetime.datetime(2000, 10, 19), datetime.datetime(2021, 1, 8)]),
                   'dates2': np.array(
                     [datetime.datetime(1998, 6, 20),
                      datetime.datetime(2012, 10, 18)])})

# Used to convert the difference in terms of months
df['nb_months'] = ((df.dates1 - df.dates2)/np.timedelta64(1, 'M'))
df['nb_months'] = df['nb_months'].astype(int)
print(df)

Output:

Example 2:

We can also get the number of days between two dates by doing a slight modification in the code. It is shown as follows:

Python3

# Importing required libraries
import pandas as pd
import numpy as np
import datetime

# Making a dataframe which will have
# two columns two store different dates
df = pd.DataFrame({'dates1': np.array(
  [datetime.datetime(2000, 10, 19), datetime.datetime(2021, 1, 8)]),
                   'dates2': np.array(
                     [datetime.datetime(1998, 6, 20),
                      datetime.datetime(2012, 10, 18)])})

# Used to convert the difference in terms of days
df['Number_of_days'] = ((df.dates1 - df.dates2)/np.timedelta64(1, 'D'))
df['Number_of_days'] = df['Number_of_days'].astype(int)
print(df)

Output:

Example 3:

In a similar way, we can get differences between the two dates in terms of weeks also.

Python3

# Importing required libraries
import pandas as pd
import numpy as np
import datetime

# Making a dataframe which will
# have two columns two store different dates
df= pd.DataFrame({'dates1': np.array(
  [datetime.datetime(2000, 10, 19), datetime.datetime(2021, 1, 8)]),
                   'dates2': np.array(
                     [datetime.datetime(1998, 6, 20),
                      datetime.datetime(2012, 10, 18)] )})

# Used to convert the difference in terms of weeks
df['Number_of_weeks'] = ((df.dates1 - df.dates2)/np.timedelta64(1, 'W'))
df['Number_of_weeks'] = df['Number_of_weeks'].astype(int)
print(df)

Output:

Example 4:

In a similar way, we can get differences between the two dates in terms of years also.

Python3

# Importing required libraries
import pandas as pd
import numpy as np
import datetime

# Making a dataframe which will
# have two columns two store different dates
df = pd.DataFrame({'dates1': np.array(
  [datetime.datetime(2000, 10, 19), datetime.datetime(2021, 1, 8)]),
                   'dates2': np.array(
                     [datetime.datetime(1998, 6, 20),
                      datetime.datetime(2012, 10, 18)])})

# Used to convert the difference in terms of years
df['Number_of_years'] = ((df.dates1 - df.dates2)/np.timedelta64(1, 'Y'))
df['Number_of_years'] = df['Number_of_years'].astype(int)
print(df)

Output: