Enter a month and year to find the last day of that month. The calculator returns the final calendar date, the day of the week it falls on, and whether the year is a leap year — useful for billing cycles, deadlines, and date math.
Last Day of Month
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Full Date
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Day of the Week
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Leap Year?
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Total Days in Month
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January, March, May, July, August, October, and December each have 31 days. April, June, September, and November have 30 days. February has 28 days in a standard year and 29 days in a leap year.
A leap year is a year with 366 days instead of the usual 365, achieved by adding an extra day (February 29) to the calendar. This adjustment keeps the calendar in sync with the Earth's orbit around the Sun.
A year is a leap year if it is divisible by 4, except for century years (e.g. 1900), which must be divisible by 400 to qualify. So 2000 was a leap year, but 1900 was not. The next leap year after 2024 is 2028.
February's shorter length dates back to the ancient Roman calendar. When Julius Caesar reformed the calendar, the extra days needed to align with the solar year were distributed across other months, leaving February with just 28 (or 29 in a leap year).
February is always the shortest month, with only 28 days in a standard year and 29 days in a leap year.
A common trick is to find the first day of the next month and subtract one day. In JavaScript, for example, new Date(year, month, 0).getDate() returns the last day of the previous month — which is the same as the last day of your target month if you pass month+1.
Knowing the last day of a month is useful for billing cutoffs, loan payment schedules, contract end dates, payroll processing, project deadlines, and any date-sensitive financial or legal calculations.
Only for February. In a leap year, February ends on the 29th instead of the 28th. All other months have the same number of days every year regardless of whether it is a leap year.