Stay in sync with international business standards using the ISO Week Number Calculator. Professional project management often relies on week numbers (W01-W53) for scheduling and reporting. Our tool accurately calculates the ISO-8601 week number for any date, helping you coordinate timelines across global teams and maintain consistent production calendars.
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ISO Week Number Calculator
Quickly find the ISO-8601 week number for any specific date. Accurate calculation following international standards. Fast, free, and 100% private browser tool.
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About ISO Week Number Calculator
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1
Select Date
Pick a date using the calendar picker or type it in manually.
2
Calculate
The ISO week number is calculated instantly for the chosen date.
3
View Details
See the week number, year, and range of dates for that week.
4
Copy
Copy the week number for your project reports or schedules.
Key Features
ISO-8601 Compliance
Follows the official international standard for identifying weeks in the year.
Range Calculation
See the exact start and end dates for the identified week number.
Year Context
Correctly handles transition weeks that span across two calendar years.
Frequently Asked Questions
Yes, we follow the international ISO-8601 standard for week numbering.
The first week of the year is the one that contains the first Thursday of January.
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