Week Number Calculator
Calculator ToolsWhich week of the year is it?
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History
All history →Week Number Calculator — at a glance
Know the week number for any date in one click.
6 Oct 2026
Find Week Number
Week 41
Day 279
How to use it — step by step
Any date.
1
Enter your numbers
Fill in the fields — sensible example values are already filled in.
2
Pick your options
Choose any dropdowns or switches that apply to your case.
3
Find Week Number
Press the button. The result is created instantly on your device.
4
Read the answer
The main answer is shown big at the top, with details below it.
Pro tips
Small things that make the result better.
✦ISO weeks start on Monday.
✦Week 1 is the week with the first Thursday of the year.
✦The first days of January can belong to week 52 or 53 of the last year.
Quick facts
Freeno signup, no limit
Instantresult in a moment
Privatenothing is uploaded
Any devicephone, tablet or PC
Frequently Asked Questions
What is an ISO week?+
A standard that numbers weeks 1 to 52 or 53, starting on Monday.
Do all countries use it?+
Many do, but the US often counts weeks starting on Sunday.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
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