Day of the Week Calculator
Fill in the value and the answer updates as you type.
How the Day of the Week Calculator works
Choose any date to see which weekday it falls on. The ISO week number follows the international standard in which weeks start on Monday and week 1 contains the first Thursday of the year. Useful for planning, birthdays, and project schedules.
Inputs and results
The Day of the Week Calculator takes 1 input and gives 4 results.
What you enter
- Date — starts at 2026-10-06.
What you get
- Day of the week
- Day of the year
- ISO week number
- Days left in the year
Day of the Week Calculator FAQ
How do I use the Day of the Week Calculator?
Enter date in the fields, then read day of the week, day of the year, iso week number and days left in the year in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Day of the Week Calculator calculate?
Find the weekday, day of year, and week number for any date. It returns day of the week, day of the year, iso week number and days left in the year from the 1 value you provide.
What values does the Day of the Week Calculator start with?
It opens with date 2026-10-06 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Day of the Week Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Day of the Week Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.