Days in Month Calculator
Instantly find how many days are in any month of any year, with leap years handled automatically — runs 100% in your browser with no upload.
29Days in this month
🔒 Calculated in your browser — nothing is uploaded.
What this tool does
Pick any month and type any year, and this tool instantly shows how many days that month has. It handles the tricky cases for you: February has 29 days in a leap year and 28 in a common year, while the other months always have their fixed length — 31 days for January, March, May, July, August, October and December, and 30 days for April, June, September and November. Because the day count is computed live from the actual calendar, you get the correct answer for past, present and future dates without memorizing the old "thirty days hath September" rhyme.
How leap years are handled
The only month whose length changes is February, and it depends on whether the year is a leap year. Under the Gregorian calendar a year is a leap year when it is divisible by 4, except for century years, which must also be divisible by 400. That is why February 2024 and February 2000 have 29 days, but February 2023 and February 1900 have only 28. This tool uses the browser's built-in date engine to apply that rule for you, so the count is always correct. Everything is calculated locally on your device — you can check as many months and years as you like with no limits.
Frequently asked questions
How does the tool know February has 29 days in some years?
It uses the calendar's leap year rule: a year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. When you enter a leap year, February shows 29 days; otherwise it shows 28.
Which months have 30 days and which have 31?
April, June, September and November have 30 days. January, March, May, July, August, October and December have 31 days. February has 28 or 29 depending on the year.
Is the year or month I enter uploaded anywhere?
No. The calculation runs entirely in your browser using JavaScript. The values you enter and the result stay on your device — nothing is uploaded, logged, or stored.