Days in Month Calculator
See how many days are in any month of any year — with the leap-year rule for February, working days and weekend days, how many of each weekday, hours in the month, a printable calendar and all 12 months side by side.
How it works
days = 31 (Jan, Mar, May, Jul, Aug, Oct, Dec), 30 (Apr, Jun, Sep, Nov) or 28/29 for February · leap year = divisible by 4, except century years, which must be divisible by 400 · working days = days − weekend days · hours = days × 24
Every month has a fixed length except February, which has 28 days in a common year and 29 in a leap year. A leap year is divisible by 4, but century years must also be divisible by 400 — so 2000 was a leap year while 1900 and 2100 are not. Beyond the day count, the calculator lays out the month as a calendar, shows which weekday it opens and closes on, and counts working days and weekend days for a Saturday–Sunday, Sunday-only or Friday–Saturday weekend. It also tells you how many Mondays, Fridays or any other weekday the month has, with their dates, how many hours, minutes and seconds it holds, its day-of-year range, ISO week numbers and quarter. A side-by-side table compares all 12 months of the year, and the total option adds up several consecutive months — handy for notice periods, rotas, rent and pay periods. Public holidays are not subtracted from working days.
Worked example
February 2026: 2026 ÷ 4 = 506.5, so 2026 is a common year and February has 28 days — exactly 4 weeks. The month starts on a Sunday (1 Feb 2026) and ends on a Saturday (28 Feb 2026), so it has exactly four of every weekday, 20 working days (Mon–Fri) and 8 weekend days, and 672 hours. With weeks starting on Sunday it fills exactly four calendar rows. February, March and April 2026 together hold 28 + 31 + 30 = 89 days.
Frequently asked questions
Which months have 31 days?
January, March, May, July, August, October and December — seven months. April, June, September and November have 30, and February has 28 or 29. The knuckle trick maps them out on your hand: knuckles are 31-day months, the gaps between them are the shorter ones.
When does February have 29 days?
Only in a leap year: divisible by 4, except century years, which must be divisible by 400. So 2024 and 2028 have 29 days, but 2026 and 2100 do not.
How many working days are in a month?
Usually 20 to 23 for a Monday–Friday week. It depends on the month length and the weekday it starts on: a 31-day month that starts on a Monday has 23, while February in a common year always has exactly 20. Public holidays are not subtracted, so take them off yourself.
How many Mondays (or Fridays) are in a month?
Every weekday appears four or five times. A 30-day month has two weekdays that appear five times, a 31-day month has three, and a 28-day February has exactly four of each. The weekday table lists the count and the dates.
How many hours are in a month?
672 hours in a 28-day month, 696 in a 29-day February, 720 in a 30-day month and 744 in a 31-day month. In places with daylight saving time, the changeover month has one hour more or less on the clock.
Why does the starting weekday matter?
It sets the whole month’s calendar layout — payroll cut-offs, shift rotas and "first Monday" rules all key off which weekday the 1st falls on, and it decides which weekdays occur five times.
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This calculator is for educational purposes. Double-check important results before acting on them.