ISO Week Date Converter
Convert a calendar date into its ISO week-year, or resolve an ISO week date.
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How to use this tool
- Choose a direction, then pick a calendar date or an ISO week and weekday.
- ISO weeks start Monday and may belong to the preceding or following calendar year.
Things to know
- Only valid ISO week dates are accepted. Week 53 exists in some years, not every year.
- One valid ISO calendar or week date in years 0001-9999. One conversion; invalid week 53 and invalid dates are rejected.
- Use no more than 200,000 characters across the input and settings.
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