Week Number Calculator

All tools

Find the ISO 8601 week number for any date, plus the week of the year, day of the year, days left in the year and the calendar quarter. Free and instant.

Pick any date to see its week number and where it falls in the year.

ISO 8601 week –
Week of year –
Day of year –
Days left in year –
Quarter –
ISO 8601 weeks start on Monday; week 1 is the week containing the year's first Thursday, so early-January or late-December dates may belong to a neighbouring year's week. The simple week of year counts calendar weeks from 1 January.
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