Dates & time

Week number and weekday

The ISO week number, weekday and day of the year for any date.

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<iframe src="https://calc.hod-group.com/embed/?hodtool=weeknum&amp;hodlang=en" title="Week number and weekday" loading="lazy" style="width:100%;max-width:720px;height:560px;border:0;border-radius:12px" data-hodcalc></iframe>
<p style="font:13px sans-serif;margin:6px 0 0">Calculator by <a href="https://calc.hod-group.com/en/week-number/">HOD Calc</a></p>
<script async src="https://calc.hod-group.com/assets/embed.js"></script>

How it works

Week 1 is the week containing the first Thursday of January (ISO 8601).

Results are for guidance only and do not replace professional advice.

Worked example

With the default values:

Date31 October 2026

you get:

Week44
WeekdaySaturday
Day of the year304 / 365
Days left in the year61

Frequently asked questions

How does the “Week number and weekday” tool work?

Week 1 is the week containing the first Thursday of January (ISO 8601).

What do I need to enter?

Just fill in: date. The result updates as you type.

Can you give an example?

Date: 31 October 2026 → Week: 44; Weekday: Saturday.

Is this calculator free, and is my data private?

Yes. HOD Calc is completely free with no sign-up. The calculation runs in your browser: nothing you type is sent or stored.