Friday the 13th Finder

Someone bets this year has three Friday the 13ths and you want to settle it, or you are picking a date for a launch, a themed party, or just avoiding signing anything on one. Type a year into the field labelled Ano and the list appears straight away, in year-month-day order. 2026 has three of them: 13 February, 13 March and 13 November.

Every year has at least one Friday the 13th and never more than three. When three turn up they follow one of two patterns: in a common year February, March and November, because a 28-day February is exactly four weeks and hands March the same starting weekday; in a leap year January, April and July. Across the 400-year Gregorian cycle the 13th falls on a Friday 688 times out of 4,800 months, more often than on any other weekday.

Type the year with all four digits. Enter just 26 and you get 1926, a leftover from the way JavaScript reads two-digit years. The list applies the Gregorian calendar to whatever year you type, so results before 1582, when the reform was first adopted, are projections that do not match the Julian calendar people were actually using at the time. The calculation happens in your browser.