How to use it
- The large number is the length of the current month, read from your own clock.
- Use the arrows, the month list or the year field to move to any other month. The table underneath shows all twelve months of that year.
- Copy copies the sentence with the month, the year and the day count.
Why the lengths differ
Seven months have 31 days, four have 30, and February has 28 or 29. The pattern is Roman bookkeeping rather than arithmetic: July and August both kept 31 days after being renamed for Julius Caesar and Augustus, and February was left to absorb the remainder.
February gets a 29th day in a leap year, which under the Gregorian rule means a year divisible by 4, except centuries, except those divisible by 400. So 2000 was a leap year, 1900 was not, and 2100 will not be. Pick February of another year in the table and the page states whether that year is a leap year, which is usually the real question behind the search.
What the chips show
- Which month of the year this is, by number.
- For the current month: how many days have passed and how many are left.
- For a February in some other year: whether that year is a leap year.
Questions
How many days are in this month?
The large number at the top of the page. The sentence under it names the month and the year so there is nothing to misread.
How many days does February have?
28 in a normal year and 29 in a leap year. Type the year into the field and the page gives the count for that specific February and says whether the year is a leap year.
Which months have 31 days?
January, March, May, July, August, October and December. April, June, September and November have 30. The table on this page lists all twelve for whichever year you pick.
How far back and forward does it go?
From year 1 to year 9999, under the Gregorian rule throughout. Dates before the calendar reform of 1582 are therefore proleptic, which matters for historians and nobody else.
