ISO 8601 weeks start on Monday. Week 1 is the first week with at least 4 days in the new year.

Week Number Calculator

Free online Week Number Calculator. Find the current ISO 8601 week number or calculate the week number for any specific date. See week start and end dates.

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Free online week number calculator tool. Process your files securely in your browser - your data never leaves your device.

Current Week Number

2/23/2026 - 3/1/2026

Select Date

IS0 8601 Week92/23/2026 - 3/1/2026

Key Features

Current ISO week display
Date to Week conversion
Week range dates (Mon-Sun)
Progress through year

Common Use Cases

Business planning
Production schedules
Payroll calculation

Frequently Asked Questions

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