How the weekday of a fixed date moves year by year
For anything pinned to a date, such as a birthday, an anniversary or a founding day, the useful question is not what weekday it falls on this year but which years it lands on a weekend. This calculator fixes one date, lists its weekday for as many years ahead as you choose, and counts how often it falls on a weekend and how often on a weekday.
Why the weekday shifts, and 29 February
365 leaves a remainder of 1 when divided by 7, so a common year pushes the weekday one place along, while a 366-day leap year pushes it two. A leap year is divisible by 4, except that a year divisible by 100 must also be divisible by 400, which is why 1900 was not a leap year and 2000 was. That rule is applied directly to find the next matching year, and a date that exists only in leap years, such as 29 February, is marked as missing in the years it does not occur.
The math uses the date components in Coordinated Universal Time, so the answer does not change with the reader time zone. As of October 2026 no external table or official recommended value is used, and public holidays and substitute holidays are not applied, so weekend means Saturday or Sunday only. Finding the next date for a given weekday is not supported. Years from 1900 to 2200 are accepted, up to 50 years at a time.
Frequently asked questions
A common year shifts the weekday by one place and a leap year by two, so the repeat usually comes after 5 or 6 years, sometimes 11. The exact year for your date is printed on the first line.
In a non-leap year that date does not exist, so the table marks it as missing and leaves it out of the weekend and weekday counts. The number of such years is reported separately.
This tool fixes the date and shows how its weekday moves year by year. Working the other way round, finding the next Wednesday from a starting date, is not supported.