Weekday Calculator: What Day Was It?
Enter a date to find its day of the week. The result also shows its day number, ISO week, days remaining in the year, and where it falls in the month.
Weekday and calendar facts
The weekday repeats in a predictable calendar cycle, while leap years add an extra day after February. The ISO week number follows an international convention: Monday is the first weekday and the first week is the one containing January 4.
Frequently asked questions
How do I find the weekday for a date?
Choose a date and calculate. The weekday calculator shows its day name and useful calendar facts.
What date range is supported?
The browser date control supports the Gregorian calendar; results are calculated for the year you enter.
What is a day of year?
It is the date’s ordinal position in its year: January 1 is day 1 and December 31 is day 365 or 366.
What week number is shown?
The result includes the ISO 8601 week number, where weeks begin Monday and week 1 contains the first Thursday of the year.