Day of the Year Calculator
Pick a date to see which day of the year it is, how many days remain, and its ISO week number.
Result
- Days remaining in the year
- 350
- Day of the week
- Thursday
- Quarter
- Q1
- Year progress
- 4.1%
- Leap year
- No, 365 days
- Ordinal date
- 2026-015
Formula
- Day of year = days since January 1 + 1
- ISO week 1 is the week containing the first Thursday of the year, and weeks start on Monday
- Leap year: divisible by 4, except years divisible by 100 that are not divisible by 400
How the Day of the Year Calculator works
The day of the year, sometimes called the ordinal date, runs from 1 on January 1 to 365 or 366 on December 31. It is used in manufacturing date codes, astronomy and programming.
ISO 8601 week numbers start on Monday. Week 1 is the week that holds the first Thursday of January, which means the first days of January can belong to week 52 or 53 of the previous year.
Worked example
January 15, 2026 is day 15 of 365, with 350 days remaining. It is a Thursday in ISO week 3 of 2026.
Frequently asked questions
What is day 100 of the year?
April 10 in a common year and April 9 in a leap year.
Is the day of the year the same as a Julian date?
In everyday use, yes. Many industries call the ordinal date a Julian date. Astronomers use Julian Day for a different continuous count of days.
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