Week Number Calculator

Find the ISO week number for today or any date, and see which dates a week covers.

Monthly Calendar Widgets

Want this on your Home Screen?

These are real widgets from the app. Get the week view widget on your iPhone Home Screen and Lock Screen - synced with iOS Calendar and Google Calendar, updated automatically.

Clean White week view widget
Monochrome week view widget
Dark week view widget
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Frequently asked questions

What week number is it right now?
The calculator shows the current ISO 8601 week number for today by default, along with the date range that week covers. Pick any other date to see its week number instead.
How are ISO week numbers defined?
Under ISO 8601, weeks start on Monday and week 1 is the week that contains the year's first Thursday. This is the standard used across most of Europe and in business and project planning, so a year can have 52 or 53 weeks.
Can I see week numbers on my iPhone calendar?
Yes. The Monthly Calendar Widgets week and month widgets give you a clean weekly view on your Home Screen, so you always know where you are in the month without opening the calendar app.

More free calendar tools