Date & time · Calendar
Day of the year calculator.
See which day of the year a date is, how many days remain, and what date a given day number falls on.
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How the day of the year is counted
The day of the year counts from 1 on January 1st. It is the number of days since January 1st of that year, plus one, which is the same formula Python's datetime library uses for its day-of-year value. A year has 365 days, or 366 in a leap year, so days remaining is the year length minus the day number.
Worked example. 8 October 2026 is day 281 of 365. That leaves 84 days, and 281 / 365 is 76.99% of the year. It is a Thursday. In reverse, day 100 of 2026 is 10 April 2026, a Friday. In a leap year such as 2028, 31 December is day 366.
Week numbers. The day of the year is not the week number. For the ISO week of a date, use the ISO week number calculator. To check whether a year is a leap year, use the leap year checker.
Frequently asked questions
What day of the year is it today?
Press Today to fill in your device date and the day number shows right away.
How many days are left in the year?
Subtract the day number from 365, or from 366 in a leap year. On day 281 of 2026 there are 84 days left.
What is the day number of December 31?
It is 365 in a normal year and 366 in a leap year such as 2028.
Is the day of the year the same as the Julian date?
No. This tool counts days from January 1st of the same year. Astronomical Julian day numbers count from a fixed point thousands of years ago.
Sources
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Runs entirely in your browser. Nothing you type is sent or stored.
Arithmetic only
Counts days on the Gregorian calendar for years 1 to 9999 and does not model historical calendar changes.