Day of the Week
Which weekday a date falls on, and how that changes year to year.
By opening this website or using its tools, you agree to our Terms and Privacy Policy.
Any date from year 1 to 9999. The proleptic Gregorian calendar is used throughout, so dates before its adoption are extrapolations rather than what people alive then would have written.
Enter a date to look up its day of the week.
Your file never leaves your browser during processing
How it works
To find what day of the week a date falls on, enter it above — the weekday appears immediately, along with the ISO week number, the day of the year, and the same date’s weekday in the surrounding years.
Weekdays follow a fixed cycle, so any date’s weekday can be computed directly rather than counted out. The calendar advances by one weekday each ordinary year and two across a leap year, which is why your birthday moves forward a day most years and jumps two after February in a leap year, and why the whole pattern repeats every 28 years in the absence of a century adjustment.
The table of nearby years is here because most real versions of this question are comparative. "When does my birthday next fall on a Saturday", "which year does this anniversary land midweek", "is the 1st a Monday in either of the next two years" — none of those are answered by a single weekday name, and all of them are answered by a short column of them. For a whole series — every third Tuesday, the last Friday of each month — generate the recurring dates instead.
Dates are computed on the proleptic Gregorian calendar, which means the modern rules are extrapolated backwards past the point where they were adopted. For anything since the eighteenth century that is what people mean. For earlier dates it is worth knowing that Britain and its colonies switched from the Julian calendar in September 1752 and skipped eleven days doing so, and most of Catholic Europe had already switched in 1582 — so a weekday computed here for a date before the local switch will not match what someone alive at the time would have written in a letter.
The ISO week number is also shown, and it has its own quirk: the week-numbering year is not always the calendar year, since the first days of January can belong to the last week of the year before. To count the days between two dates rather than name one, use the date difference calculator.
FAQ
What day of the week was I born on?
Enter your date of birth above. The weekday appears immediately, along with the day of the year and the ISO week it fell in.
Why does my birthday fall on a different weekday each year?
An ordinary year is 365 days, which is 52 weeks plus one day, so the date shifts forward one weekday. A leap year adds a second day of shift for any date after February.
How far back and forward does this work?
From year 1 to year 9999. Dates before the local adoption of the Gregorian calendar are extrapolations and will not match the weekday recorded at the time.
What is the ISO week number?
A week numbering scheme where weeks start on Monday and week 1 is the one containing the first Thursday of January. Because of that rule, early January dates can belong to week 52 or 53 of the previous year.
When will this date next fall on a weekend?
The table of nearby years shows the weekday for the same date across six years, which is usually enough to spot the next weekend occurrence.