Week Number Calculator
Free week number calculator. Find the ISO week number for any date.
Your files are processed directly in your browser whenever possible.
How to use
- 1Pick a date.
- 2Read the ISO week number and week-year.
How it works
Week Number Calculator runs in your browser whenever possible. Your data stays on your device and is not uploaded to our servers unless a feature explicitly requires it.
Example
13 August 2026 is ISO week 33.