Day of Year Calculator
See which day of the year a date is, and turn a day number back into a date.
Date or day number
Both calculations update as you type.
Day 1 is January 1. Leap years have 366 days.
Enter a year and a day number.
How to use this calculator
- 1
Pick a date. The day number, days remaining, leap-year status, weekday and ISO week appear.
- 2
Or enter a year and day number. The date is shown under “Day number to date”.
- 3
Mind the leap year. Day 60 is March 1 in an ordinary year but February 29 in a leap year; day 366 exists only in leap years.
Example
October 20, 2026 is day 293 of 365, with 72 days left. It is a Tuesday in ISO week 43.
Day 60 of 2024 is Thursday, February 29, 2024; day 60 of 2026 is Sunday, March 1.
How it is calculated
The day of the year counts calendar days from January 1 (day 1) and includes the day itself. Days remaining are the days left after the chosen date until December 31. A year is a leap year if it is divisible by 4, except for century years not divisible by 400: 2000 and 2024 are leap years, 1900 and 2100 are not.
An ordinal date such as 2026-293 is the ISO 8601 way of writing a year and day number. It is not the same as a Julian date or Julian day number used in astronomy.