Why was 1900 not a leap year?

The Gregorian rule makes years divisible by 4 leap years, except those divisible by 100 that are not also divisible by 400. 1900 divides by 100 but not 400, so it was a common year; 2000 divides by 400, so it was a leap year.

Does February always have 28 days?

28 in a common year and 29 in a leap year. The rest are fixed: January, March, May, July, August, October, and December have 31; April, June, September, and November have 30.

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Days in Month Calculator

Check how many days a given month has, with the whole year and leap-year status.

Input

Year

Month

Days per month

Month	Days	Weekday
January	31	Thursday
February	28	Sunday
March	31	Sunday
April	30	Wednesday
May	31	Friday
June	30	Monday
July	31	Wednesday
August	31	Saturday
September	30	Tuesday
October	31	Thursday
November	30	Sunday
December	31	Tuesday

Days in the year365

Common year2026

About this tool

Pick a year and month to see how many days it has, along with all twelve months of that year and whether it is a leap year. The rule is every four years, but not century years, unless they divide by four hundred — which is why 1900 was not a leap year and 2000 was. That exception is exactly where hand-written checks tend to go wrong.

How it works

Choose a year and a month.
Read the day count and leap-year status.
Compare against the twelve-month table for that year.

Assumptions

Applies the Gregorian leap year rule: every four years, except centuries, except every four hundred years.

Privacy

Every calculation runs inside this browser. Dates and birthdays are never uploaded, stored, or written to the URL or any log.

Frequently asked questions

Why was 1900 not a leap year?: The Gregorian rule makes years divisible by 4 leap years, except those divisible by 100 that are not also divisible by 400. 1900 divides by 100 but not 400, so it was a common year; 2000 divides by 400, so it was a leap year.
Does February always have 28 days?: 28 in a common year and 29 in a leap year. The rest are fixed: January, March, May, July, August, October, and December have 31; April, June, September, and November have 30.

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