What Week Number Is It?
The current week number is at the top. It is counted according to ISO 8601, as is common in most of Europe and in Outlook and most calendars. For another date, look it up below.
Calculation based on ISO-8601 standard.
How it works: What Week Number Is It?
- Read the current week at the top.
- For another date, pick it in the field.
- Click calculate.
All features are available in the tool Calendar Week Calculator.
Frequently asked questions
How are week numbers counted?
The week starts on Monday. Week 1 is the week containing the first Thursday of the year, so the first days of January can still belong to the last week of the previous year.
Does every year have 52 weeks?
No. A year that starts on a Thursday, or a leap year that starts on a Wednesday, has 53 weeks.
How does this tool work?
Quickly determine the current calendar week or convert any date into a week number.
The tool instantly shows you today's calendar week. Use the date field to select a specific day to determine its CW number according to the ISO-8601 standard. This is particularly helpful for scheduling and project coordination.
Where are my data processed?
Only in your browser. Your data is not sent to any server.
The tool calculates and converts with JavaScript right on your device. Input and files are not sent to us or anyone else. You can check this yourself: load the page, disconnect from the internet, and the tool keeps working in the open tab.