What is ISO week date?

The ISO week date system numbers weeks from 1 to 52 or 53, with weeks starting on Monday and week 1 being the week containing the first Thursday of the year.

2 tools that work with ISO week date

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Date & Time Tools2

Day of Year CalculatorFind the ordinal day number, week number, quarter and how much of the year has elapsed.ISO Week Number CalculatorFind the ISO 8601 week number, quarter and day of year for any date.

Related terms

Terms that appear alongside ISO week date on the same tools.

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