Weekly digest
Pick the categories you care about: movies, AI launches, sports, eclipses, and major public dates. One email per week, and never anything you did not ask for.
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Date calculator
Find the ISO week number for any date
Date math depth
Reference fields include the calculator slug, translated title, worked example, edge cases, FAQ, and companion route when one exists.
Week number calculator
The dedicated week-number page compares ISO, US Sunday-start, and simple week systems.
Open Week number calculator →ISO 8601. Week 1 is the week containing the first Thursday of the year. Weeks start on Monday.
