Day of Year Calculator
See which day of the year today is — out of 365, or 366 in a leap year — plus the days remaining, the week number, and how much of the year is complete. Enter any date, or leave the field blank for today.
Day-of-year (the 'ordinal date' or, loosely, 'Julian date') runs Jan 1 = day 1 through Dec 31 = day 365 or 366. Everything after February shifts by one in leap years.
Ordinal dates and where they're used
Numbering days 1 through 365 (or 366) gives every date a single coordinate — no month lengths to remember. Pilots and meteorologists log with it, food packagers stamp it (a '195' pack date means the 195th day of the year), and ISO 8601 formalizes it as the ordinal date, like 2026-195.
Two things trip people up. First, leap years: every date from March 1 onward is one day later in the count, so March 1 is day 60 in common years but day 61 in leap years. Second, week numbers: this page counts simple 7-day blocks from January 1, while the ISO week system starts weeks on Monday and can assign January 1 to week 52 or 53 of the previous year.
How it’s calculated
Day of year = round((date − Jan 1 of the same year) / 86,400,000 ms) + 1, both dates at noon. Leap year when divisible by 4 and not by 100, unless divisible by 400 (Gregorian rule) — giving 366 days. Days remaining = year length − day number. Week = ceil(day ÷ 7), counting Jan 1-7 as week 1. Progress = day ÷ length × 100.
Week numbers here are simple 7-day blocks from Jan 1, not ISO 8601 weeks, which start on Mondays and can differ by one.
Day numbers for the first of each month
| Date | Common year | Leap year |
|---|---|---|
| Feb 1 | 32 | 32 |
| Mar 1 | 60 | 61 |
| May 1 | 121 | 122 |
| Jul 1 | 182 | 183 |
| Oct 1 | 274 | 275 |
| Dec 1 | 335 | 336 |
Computed from cumulative month lengths; leap column adds one from March onward (Gregorian calendar).
Common mistakes
- Using a common-year chart in a leap year — every date after Feb 29 is off by one.
- Confusing this simple week count with ISO week numbers, which start weeks on Monday and can label Jan 1 as week 52/53 of the prior year.
- Calling it a 'Julian date' in the astronomical sense — that's a continuous day count from 4713 BC, a different quantity.
- Computing days left as 365 − day in a leap year (it's 366 − day).
Frequently asked questions
How is the day of the year calculated?
Day = (your date − January 1 of that year) in whole days + 1. July 14, 2026 is day 195 because 194 days elapse after January 1, and 2026 has 365 days, leaving 170.
Which day of the year is today out of 365?
Leave the date blank and the top line answers directly — for example 'Day 195 of 365'. In a leap year the denominator becomes 366.
Is day-of-year the same as the Julian date?
Colloquially people say 'Julian date' for the 1-365 number, and food dating uses it that way. Astronomers mean something else: a running day count since 4713 BC. This page computes the calendar (ordinal) version.
Why is my week number different from my planner's?
This tool counts plain 7-day blocks from January 1. Planners often use ISO 8601 weeks, which start on Monday and define week 1 as the week containing the first Thursday — the two systems can disagree by one week.