Last Day of Month Calculator

About this calculator

This calculator returns the final calendar date of any month you enter — the 28th, 29th, 30th or 31st — along with the day of the week it falls on. Most months have a fixed length, but February's length depends on the Gregorian leap year rule: a year is a leap year if it is divisible by 4, except years divisible by 100 unless they are also divisible by 400 (so 2000 was a leap year, but 1900 was not).

Knowing the exact last day of a month, and which weekday it lands on, matters for billing cycles that run to end-of-month, payroll runs, rent due dates, accounting close dates, subscription renewals, and any deadline defined as “the last business day of the month,” where you also need to check whether that date falls on a weekend.

Enter a year and month and the calculator instantly works out the last date, the total number of days in that month, and the corresponding weekday, so you do not have to count on your fingers or check a paper calendar.