How to use the days in month calculator
- Choose the Month from the list. It starts on February, the month people most often check.
- Type the Year (1 to 9999).
- Read Days, then Weeks (four weeks plus the extra days), Weekdays (Mon–Fri), the First day and Last day, and whether the year is a leap year.
- Scroll to the table, Every month of your year, for days, starting weekday and weekdays in all 12 months.
What it does and when to use it
Month length matters in more places than calendars. Daily rates for rent or pay are often worked out as the monthly amount divided by the days in that month. Timesheets and shift rotas need the number of weekdays. Budget and habit trackers need to know whether a month has 28, 29, 30 or 31 boxes. Teachers and parents can use the year table as a quick reference sheet.
For the leap-year rule itself, with the next and previous leap years, use the leap year checker. To count working days between any two dates, with holidays removed, use the business days calculator. To find the date a number of days or months ahead, use add or subtract days.
How it works
April, June, September and November always have 30 days, February has 28 or 29, and the rest have 31. February gets 29 when the year passes the Gregorian leap-year test. The first and last weekdays come from a day count since 1 January 1970, and weekdays are counted by removing every Saturday and Sunday in the month. No clock time is used, so the answer does not depend on your time zone.
Worked examples
February 2024. A leap year, so 29 days: four weeks and one day. It started and ended on a Thursday, which gave Thursday five appearances, and it had 21 weekdays. In the year table the row reads February | 29 | Thursday | 21.
September 2026. 30 days, starting on a Tuesday and ending on a Wednesday, with Weekdays (Mon–Fri): 22. The same table shows that 2026 ranges from 20 weekdays (February) to 23 (July and December).
February 1900. Only 28 days, because 1900 is a century year not divisible by 400. The tool confirms 1900 is: a common year (365 days).
Limits and tips
- The tool uses the Gregorian calendar for all years, including years before it was introduced in 1582.
- Weekday counts assume a Saturday–Sunday weekend.
- The year table is handy to copy into a planner: it lists every month’s length and starting weekday at once.
Frequently asked questions
How many days does February have?
Why do two months with 31 days have different weekday counts?
Are public holidays removed from the weekday count?
Is there an easy way to remember month lengths?
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