yukt.tools
calendar utility

Week Number Calculator

Find the ISO week number, ISO week-year, weekday, day-of-year, quarter, and exact week ranges for a calendar date.

Date lookup

ISO week numbers always start on Monday

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Display week rangeMonday start

The ISO week value stays Monday-based; this only changes the extra displayed range.

Fast dates

Week details

Run a date to calculate the ISO week

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ISO week appears here

Run the calculator to show week number, week-year, day position, and copy-ready ranges.

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