The number of a date within its year
Pick a date and the page returns its position in the year, counting 1 January as day 1. The next lines show days left until 31 December, the weekday, and a plain yes or no on whether the year is a leap year. Today's values are filled in when the page opens.
Day numbers show up in logistics, manufacturing batches, data logs and project burn-down charts. A date written as day 71 is short and sorts cleanly, but it is hard to read by eye. This page does the counting for you, so you can read the plain date and the number together.
Leap years shift every date after February. 1 March is day 60 in an ordinary year and day 61 in a leap year, so a day number alone does not name one date unless you also know the year. The leap-year line is there so you can see that straight away.
A leap year is one divisible by 4, except century years that are not divisible by 400. So 2000 and 2028 were or will be leap years, while 1900 and 2100 are not. For the year-plus-day label format, see the Julian date converter.
Worked examples
Questions about this tool
Is 1 January always day 1?
Yes. Counting starts at 1 on 1 January in every year.
How do I know if a year is a leap year?
The page tells you. By rule, years divisible by 4 are leap years, except centuries not divisible by 400, so 2100 is not.
Is this the same as a Julian date?
The year-plus-day label uses the same day number. The astronomical Julian day number is a different, much larger count.