What is Week Number Calculator?
Enter a date to see its ISO 8601 week of the year (weeks start on Monday), its week of the month (the week containing the month's first Thursday is week 1), and the Monday–Sunday dates of that week. Or enter a year and week number to get that week's date range.
How to use
- 1
Choose date → week number or week number → dates.
- 2
Enter a date, or a year and week number.
- 3
Check the week number and date range.
Use cases
Work reports
Find the week number to put on your weekly report.
Scheduling
Figure out when “W42” mentioned by a colleague is.
FAQ
Is the information I enter saved?+
No. All calculations happen in your browser and nothing is stored or sent anywhere.