Day of the Week Calculator

Find out what day of the week any date falls on, whether it is decades in the past or years into the future.

How this works

Pick any date and the calculator returns the day of the week it falls on, using the Gregorian calendar throughout. It also reports the ISO week number, the day of the year, the quarter, whether that year is a leap year, and which day of the week the same date falls on next year, since a date does not land on the same weekday every year. For example, July 20, 1969, the day of the Apollo 11 Moon landing, falls on a Sunday.

Why the same date is not always the same weekday

A normal year has 365 days, which is 52 weeks and 1 extra day, so a fixed date moves forward by one weekday each year. A birthday that falls on a Tuesday this year falls on a Wednesday next year, in a normal year. A leap year adds a second extra day, which pushes the weekday forward by two instead of one for anyone whose date falls after February 29 in that year. This is why a date returns to the same weekday roughly every 5 to 6 years, not every year.

How far back the calculation works

The result uses the Gregorian calendar for every date, including ones before it was adopted. Most of Europe adopted the Gregorian calendar between 1582 and the early 1600s, Great Britain and its colonies in 1752, and some countries not until the early 20th century. For a date before your country's adoption year, historical records may show a different weekday than this calculator returns, because they were kept using the older Julian calendar at the time.

Common questions

Enter your date of birth and the result shows the weekday it fell on. Most people are surprised to learn their birth weekday, since nobody remembers being born and it is rarely written down anywhere.
A year is 52 weeks plus 1 day (or 2 days in a leap year), so a fixed calendar date shifts forward by one weekday most years, and by two across a leap year that includes February 29 before your date. It takes roughly 5 to 6 years, depending on how the leap years fall, for a date to land back on the same weekday.
Yes, for any date, using the Gregorian calendar throughout. For dates before your country adopted the Gregorian calendar, historical sources may record a different weekday, since they used the Julian calendar at the time.
ISO 8601 numbers weeks from 1 to 52 or 53, with week 1 defined as the week containing the year's first Thursday. It is the week-numbering standard used in Europe and in most business and engineering contexts, and differs from the "week of the year" some US calendars show.

Continue with

All tools
Date Difference Days, weeks, months and years between two dates. Age Exact age in years, months and days. Days Ago The exact date a given number of days ago. Days Until How many days remain until a date. ISO Week The ISO week number and week-year for any date.