📆 Day of the Year Calculator
Enter a date to get its day-of-year number (Jan 1 = 1), how many days are left in the year, and how much of the year has passed.
Day 236 of 365
Monday · 129 days remaining · 64.7% of the year elapsed
The ordinal (day-of-year) number counts from January 1 = 1. Leap years have 366 days. 🔒 Computed in your browser.
How the day of the year calculator works
The tool counts whole days from January 1 (day 1) to your chosen date to give the ordinal day-of-year, sometimes called the Julian day in everyday (non-astronomical) use. It also reports the days remaining until December 31 and the share of the year elapsed. Leap years are handled automatically, so any date in a leap year counts up to 366.
The ordinal day-of-year shows up in logistics, manufacturing lot codes, spreadsheets and scientific data, where dates are recorded as “day 213” rather than a calendar date. Note this is the plain ordinal day, not the astronomical Julian Day Number (a continuous count since 4713 BC). Everything is computed locally in your browser.
Frequently asked questions
What is the day of the year for a date?
It’s the ordinal count from January 1. For example March 1 is day 60 in a common year and day 61 in a leap year, because February has an extra day.
How many days are in a leap year?
366 — leap years add February 29. A year is a leap year if it’s divisible by 4, except century years, which must be divisible by 400 (so 2000 was a leap year but 1900 was not).
Is this the same as a Julian date?
In casual use “Julian date” often means exactly this ordinal day-of-year (e.g. day 045). It is not the astronomical Julian Day Number, which is a continuous day count used in astronomy.
How many days are left in the year?
The tool subtracts the day-of-year from the year’s total (365 or 366) to show the days remaining through December 31, and the percentage of the year that has elapsed.
Is my date uploaded?
No — the calculation runs entirely in your browser and works offline.