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Productivity

Day of Week Finder

Find the weekday, ISO week, and day-of-year for any date.

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Date lookup

Weekday:     Thursday
Day of year: 141 of 365
ISO week:    20
Month:       May
Quarter:     Q2
Leap year:   no

Frequently asked questions

What is an ISO week number?
ISO 8601 weeks run Monday through Sunday, and week 1 is the week containing the first Thursday of the year. This standard is used widely in Europe and in business reporting.
How is day of year calculated?
It counts how many days have elapsed since January 1, with January 1 being day 1 and December 31 being day 365 or 366 in a leap year.
Does it work for dates in the past or future?
Yes. Enter any date and the tool returns the weekday, ISO week, and day-of-year using the Gregorian calendar, including leap-year handling.