The day of the year (or ordinal date) numbers every day from 1 to 365, or to 366 in a leap year. January 1 is day 1, February 1 is day 32, and December 31 is day 365. For example, October 3, 2026 is day 276 of 2026, leaving 89 days in the year. Our today page always shows the current day number.
How to find the day number of any date
Add the date's day of the month to the number of days before that month starts:
| Month | Add to the date (common year) | Leap year |
|---|---|---|
| January | 0 | 0 |
| February | 31 | 31 |
| March | 59 | 60 |
| April | 90 | 91 |
| May | 120 | 121 |
| June | 151 | 152 |
| July | 181 | 182 |
| August | 212 | 213 |
| September | 243 | 244 |
| October | 273 | 274 |
| November | 304 | 305 |
| December | 334 | 335 |
Examples for 2026 (a common year):
- February 14 → 31 + 14 = day 45
- July 4 → 181 + 4 = day 185
- December 25 → 334 + 25 = day 359
In a leap year such as 2028, add one extra day to every date from March 1 onward. See how leap years work.
Milestone day numbers
| Day number | Common year | Leap year |
|---|---|---|
| Day 100 | April 10 | April 9 |
| Day 183 (middle of a common year) | July 2 | July 1 |
| Day 200 | July 19 | July 18 |
| Day 256 ("Programmers' Day") | September 13 | September 12 |
| Day 300 | October 27 | October 26 |
| Last day | Day 365, December 31 | Day 366, December 31 |
July 2 is the exact midpoint of a common year: 182 days before it and 182 after. Watch the year tick by with the year progress bar.
"Julian dates": the YYDDD format
In business, manufacturing and the military, a "Julian date" usually means a compact code made of the year plus the day number. It's not related to the Julian calendar, but the name has stuck.
- YYDDD: October 3, 2026 → 26276 (year 26, day 276).
- YYYYDDD: the same date → 2026276. This matches the ISO 8601 ordinal date, usually written 2026-276.
- YDDD: some products use only the last digit of the year: 6276.
You'll find these codes on canned and packaged food, eggs, batteries, tires and pharmaceutical batches, and in US military logistics. US egg cartons, for example, show the pack date as a three-digit day number from 001 to 365. To decode one, look up the day number in the table above. A code of 045 means February 14.
Always check the manufacturer's format, though: the code on a package can be a production date, a pack date or a best-by date, and some brands use their own systems.
The astronomers' Julian Day
Astronomers use a different idea with a similar name: the Julian Day (JD), a continuous count of days since noon UTC on January 1, 4713 BC in the proleptic Julian calendar. It lets scientists measure the time between events without worrying about months, years or calendar reforms. At noon UTC on October 3, 2026, the Julian Day number is 2,461,317. Each Julian Day begins at noon, a convention that kept a single night of observations under one date.
A related version, the Modified Julian Date (MJD), subtracts 2,400,000.5 to give smaller numbers that start at midnight. It's widely used in satellite tracking and space science.
Day numbers vs week numbers
Day numbers count days; week numbers count weeks. Many workplaces in Europe plan by ISO week number (week 1 to 52 or 53). Our ISO week numbers guide explains the rules, and what week is it shows the current week.
How much of the year is left? Days left in 2026 counts down the remaining days, and how to count days between two dates uses day numbers to make the math easy.
Frequently asked questions
What day of the year is December 25?
Day 359 in a common year, or day 360 in a leap year.
What is today's Julian date?
In the YYDDD format, it's the two-digit year followed by today's day number. October 3, 2026 is 26276.
Is the Julian date the same as the Julian calendar?
No. Despite the name, YYDDD codes use the modern Gregorian calendar. The Julian calendar is the older system introduced by Julius Caesar.