Day of the Year Calculator
Find the ordinal day number and ISO week for any date.
Where a date sits in the year
The ordinal day of the year — day 1 through 365 or 366 — turns up in logistics, scientific data, and file naming. This tool gives that number for any date, plus how much of the year is left.
It also reports the ISO 8601 week number, the Monday-based standard used across Europe and in business calendars. Enter a date and you get its day count, percentage through the year, and week number at once.
Complete and private
It computes the ordinal day and ISO week in your browser, so nothing you enter is uploaded.
Frequently Asked Questions
What is the day of the year?
A number from 1 to 365 or 366 counting from January 1. March 1 is day 60 in a common year, day 61 in a leap year.
What is the ISO week?
The ISO 8601 week number, where week 1 is the week containing the first Thursday of the year, and weeks start on Monday.
Why is this useful?
Ordinal dates appear in logistics, science, and file naming, and the days-remaining figure is handy for year-progress tracking.
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