Day of the Week Finder for Any Date
Find the day of the week, day of the year and ISO week number of a date, in your browser.
Friday
Day of week
205 / 365
Day of year
30
ISO week
No
Leap year
100% local computation (Gregorian calendar).
🔒 100% client-side — no data sent
Instantly find the day of the week, the day of the year and the ISO week number for any given date. The tool runs directly in your browser with no sign-up, handy for calendar and scheduling calculations.
What is it for?
- ▸ Find out which weekday a birth date or anniversary falls on.
- ▸ Get the ISO week number to organize a project schedule.
- ▸ Know the day of the year (ordinal date) for an administrative calculation.
- ▸ Check the weekday of a future date such as a deadline or appointment.
FAQ
What is the ISO week number?
It is the week numbering defined by the ISO 8601 standard, where weeks start on Monday and week 1 contains the year's first Thursday.
Can I test past or very old dates?
Yes, you can enter past or future dates and get the matching day of the week.
What is the day of the year?
It is the ordinal date, meaning the position of the date within the year, from 1 on January 1st up to 365 or 366 on December 31st.