A related question.

What is the common understanding of 1 month notice?

If I tender on the 1st of the month, does this mean my last day of work will be:

a) 28th/29th/30th/31st of the month (last day of the calendar month)
b) Same day of the following month i.e. 1st of the following month
c) Same day of the following month - 1 day
d) Date of resignation plus 30 days (inclusive of non-working days and weekends)

How to calculate the correct last day based on HR standard?