Pevlika

Week Number Calculator

See today’s week number instantly, check any date, or find the dates for a given week.

Runs in your browser — nothing is uploaded
Find

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How to use Week Number Calculator

  1. Leave the date empty for today, or pick any date.
  2. Read the ISO week number and its Monday–Sunday range.
  3. Switch to “Dates of a week number” to go the other way.

Questions

What is an ISO week number?

ISO 8601 weeks start on Monday, and week 1 is the week that contains the year’s first Thursday. A year has 52 or 53 ISO weeks, and a few days around New Year can belong to the neighbouring year’s week.

Why is the US week number different?

Many US calendars start weeks on Sunday and count the week containing 1 January as week 1, so the number can differ by one from the ISO week.

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