Previous Up Next

Special dates

Certain dates, when written down in figures, have a very interesting appearance. On this page a list of such special date. It is important to note that throughout the world different formats are used to write down dates. Some common formats are: Of course, there is also a choice from the number of digits you chose to represent the day, month and year. Some of these are: From these many different date formats can be constructed.

Same number dates

These are dates which all use the same number. Some examples are:

Double dates

These are dates which consist of twice the same number.


All double dates of this form are in the past. The last of dates of this form was:



Double dates of this form, always appear in the first 12 years of the century. There are a total of 257 of these day with the first being January 1, 1001 and the last being December 31, 3112. Some close double dates of these form are:


Sqaure root days

Examples of Square root days are:

Palindrome dates

A palindrome is a word, number or sentense which reads the same in reverse order. Of course, there are also palindrome dates (when ignoring all separation symbols). Below a number of these dates are given, grouped by their format.


There are about 31 centuries having palindrome dates of this format. Most of these centuries have twelve palindrome dates, one for each month. There are a total of 331 of such palindrome dates. Some close palindrome dates of this format are:


Each century has twentyfour palindrome dates of this format, and they always occur on the eleventh and the twentysecond of the month. Some close palindrome dates of this format are:


These kind of palindrome dates only occur in twelve centuries, namely, those starting with 10, 11, 20, 21, 30, 40, 50, 60, 70, 80, and 90. And in each of those ages, they every time occur in the same month. There are a total of 335 of such palindrome dates. Note that these never occur in October, as that would make a 01YY year, however these dates, when written as DD-MM-YYY are still palindrome dates.


With this palindrome the only possible month is November (11). Which means there are 30 of these palindrome date in each century. Some of the close palindrome dates of this format are:



There are a lot of these kind of palindrome dates, especially in the first centuries. Till December 31, 9999, there are 4090 of these kind of palindrome dates, which makes it the most common form of palindrome date (when the year is not abbreviated).


Again, there are many of these kind of palindrome dates. 4123 till December 31, 9999, to be precise. As to be expected consequentive palindrome dates of this form, often occur in the same month.

(D)D-(M)M-YY and/or YY.(M)M.(D)D

Of course, these also include many DD-MM-YY and YY.MM.DD palindrome dates.

"Digital" mirror dates

When using the "digital" numbers consisting of seven segments, there are also mirror dates, which read the same in the mirror. These are rather rare, because they can only make use of the digits 0, 2, 5, and 8. (One could also include the digit 1, which in the mirror reads like 1 as well, but then in the wrong place.)


All mirror dates of this form lay in the future. They are:


All mirror dates of this form are: