Week Number

What is Week Number?

ISO week numbers provide a standardized way to refer to a specific week in a year — useful in project planning, fiscal reporting, and scheduling systems. DailyDevTools' Week Number tool shows the current ISO week number, lets you look up the week number of any date, and lists all weeks in a year with their date ranges — bridging the gap between calendar dates and week-based planning.

How to use Week Number

1. 1Open the tool to see the current ISO week number and date range for this week
2. 2Enter any date to look up its week number
3. 3Browse the full-year calendar table showing all 52 (or 53) weeks and their start/end dates
4. 4Use the year selector to view week numbers for past or future years

Frequently asked questions