How do you know if February has 28 or 29 days?

February has 29 days in a leap year and 28 otherwise. A year is a leap year when it is divisible by 4, except for century years (like 1900), which must also be divisible by 400 (so 2000 was a leap year but 1900 was not).

Which months have 31 days?

January, March, May, July, August, October and December have 31 days. April, June, September and November have 30. February has 28 or 29.

Is anything sent to a server?

No. The calculation runs entirely in your browser and nothing is uploaded.

Days in Month Calculator

How many days are in any month of any year?

How many days are in a month?

Pick a month and year to see exactly how many days it has, whether the year is a leap year, and which weekdays the month begins and ends on.

The only month that changes length is February, which has 29 days in a leap year and 28 otherwise. A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. Everything is calculated locally in your browser.