How this calculator works
Each date is written as an unseparated string in the chosen order and year width, then compared with its own reverse. Padding matters because it changes the length of the string: 2 February 2020 is the palindrome 02022020, but the unpadded 222020 is not one. The finder scans dates one day at a time from the start date and stops when it has enough matches or reaches the range limit.
Formula
Build S = DD MM YYYY, MM DD YYYY, DD MM YY or MM DD YY depending on the choices, using two-digit day and month and a four or two-digit year. A date is a palindrome when S equals its reverse. The day and month may be unpadded if that option is selected.
Worked example
In the padded day-month-year format the next palindromes after 2026-11-01 are 2030-02-03 (03022030), 2031-02-13 (13022031) and 2032-02-23 (23022032). In 2020, the padded date 2020-02-02 gave 02022020.
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Frequently asked questions
Why are palindrome dates different in different countries?
Because the same date is written in a different order. 2 March 2030 is 03022030 in day-month-year form and 02032030 in month-day-year form, and only the first is a palindrome. The format selector lets you test the convention you actually use.
Do leading zeros count?
That is a choice. Many lists of palindrome dates use padded two-digit days and months, which makes short dates longer and can create palindromes that disappear without padding. The page shows the exact string it tested in the second column.
Are two-digit years included?
Yes. With a two-digit year the string is six digits long, so matches are more common. The year is taken modulo 100, so 2030 becomes 30.
How far ahead does the next-date mode search?
Up to 100 years. A four-digit day-month-year palindrome is relatively rare, so the next few can be years apart. If no match is found the table is empty and the count is zero.