Date difference different results in Excel vs Python

Question

I have a pandas data frame with two dates columns with timestamps ( i want to keep a timestamp) I want to get the difference in days between those two dates, I used the below. It works just fine.

mergethetwo['diff_days']=(mergethetwo['todaydate']-mergethetwo['LastLogon']).dt.days

The doubt is, when I got the difference between those two dates in Excel, it gave me different numbers.

In python for example the difference between

5/15/2020 1:48:00 PM (LastLogon) and 6/21/2020 12:00:00 AM(today date) is 36 .

However, in Excel using

DATEDIF =(LastLogon,todaydate,"d") 5/15/2020 1:48:00 PM and 6/21/2020 12:00:00 AM is 37 days !

Why is the difference? Which one should I trust? As I have 30,000 + rows, I can't confirm all of them.

Appreciate your support Thank you

Answer 1

To calculate the date difference, we can use the function  DATEDIF() 
The syntax for the same is =DATEDIF(Start_Date, End_Date, Metric)
where, start date is the first date u want to calculate from
and end date is the last date 
Metric is 

• “d”: Days
• “m”: Months
• “y”: Years
  It’s important to note that this function won’t automatically appear in Excel until you completely type =DATEDIF