How Many Days in This Month?
There is no single answer — the count rotates between 28, 29, 30 and 31, and "this month" means something different every time you ask. The panel below answers it for the month you're actually in, right now, and quietly tracks the two things people really want: the total, and how many days are left.
Why "this month" never has one answer
Seven months have 31 days — January, March, May, July, August, October and December. Four have 30: April, June, September and November. That leaves February, the only month whose length actually moves: 28 days most years, 29 in a leap year. Every other month is fixed forever, so the entire question really hangs on one thing — whether the year you're in is a leap year.
The rule that decides it is the Gregorian one, introduced under Pope Gregory XIII in 1582: a year is a leap year if it divides by 4 — except century years, which must also divide by 400. So 2000 was a leap year, 1900 was not, and 2100 won't be either. The checker further down applies that rule for any year you type in.
Two different questions, one search box
Most people typing this aren't curious about the calendar — they're counting toward something. Half want the total: rent, salaries, subscription billing and interest all key off how many days the month contains, which is why a daily-rate or a pro-rated invoice changes depending on whether you're in February or a 31-day month. The other half want the days remaining — the genuinely anxious version of the question, asked with a deadline or a payday in mind. The panel above shows both at once, so neither group has to do the subtraction.
Working days left — and why your number may differ
The panel also splits the remaining days into weekdays and weekend days, which is closer to what most people mean by "days left" at work. One caveat: it counts plain calendar weekdays only. It can't know your local public holidays, which vary by country and even by state — so if there's a bank holiday ahead, your true working days will be one or two fewer. For the bigger picture across a whole year, see how many work days are in a year.
Why the months are uneven at all
The lopsided pattern is inherited from Rome. Julius Caesar's calendar reform of 46 BC set month lengths close to the ones we use, alternating long and short months to fit a 365-day year. The familiar playground story goes further: that the emperor Augustus later stole a day from February so that his month, August, would have 31 days and not be outdone by Caesar's July.
It's a tidy story, and almost certainly not true. It traces back to the 13th-century writer Sacrobosco, and most historians now reject it — the uneven lengths appear to predate Augustus entirely. The honest answer is that the months are uneven because the Roman calendar was a centuries-long patch job, not a clean design. For the trick to actually remember which months are which, the knuckle method lives on how many days are in each month.
Check any month
Pick a month and year — handy for a future deadline, a past date, or settling whether a particular February had 29 days.
Frequently asked questions
How many days are left in this month?
The panel at the top shows it live — "days left after today", split into weekdays and weekend days, with a countdown ticking down to midnight on the 1st of next month.
Does this month have 30 or 31 days?
It depends which month you're in. Seven months have 31 days and four have 30. The live count at the top of the page reads it straight from today's date, so you don't have to remember the pattern.
Does this month only have 28 days?
Only February can — and only in a non-leap year. In a leap year February has 29. No other month ever has fewer than 30.
Why isn't every month the same length?
Because the calendar is inherited from Rome rather than designed. A clean system would give every month about 30.44 days — the average — but we keep whole-day months of 28 to 31 instead.
- Gregorian calendar leap-year rule — established by the papal bull Inter gravissimas under Pope Gregory XIII, 1582 (divisible-by-4, century exception, divisible-by-400 rule).
- timeanddate.com — monthly calendars and month-length reference for any year.
- Julian calendar reform, 46 BC — the origin of the modern month lengths and the alternating long/short pattern.
- The "Augustus took a day from February" account traces to Sacrobosco (13th c.) and is rejected by most modern calendar historians.
So there's no permanent answer to "how many days in this month" — only today's answer, and the one quietly ticking down at the top of the page.