Friday the 13th calculator
Find every Friday the 13th, or the years a date lands on the weekday you want.
Which months have a Friday the 13th in 2026?
February, March, November. That is 3 Friday the 13ths, the most a year can have. The next years with their months: 2027 (Aug); 2028 (Oct); 2029 (Apr, Jul); 2030 (Sep, Dec); 2031 (Jun).
How often does Friday the 13th happen?
Over the 400-year cycle of the Gregorian calendar there are 688 Friday the 13ths, about 1.72 a year. Every calendar year has at least one and none has more than three. In a 400-year cycle, 171 years have one, 170 have two and 59 have three (we counted every year from 2000 to 2399). Two Friday the 13ths are between 1 and 14 months apart.
Is the 13th really more often a Friday than any other day?
Yes, by a small margin. In the same 400 years the 13th falls on a Sunday 687, Monday 685, Tuesday 685, Wednesday 687, Thursday 684, Friday 688, Saturday 684 times, out of 4800 months. Friday is the most common; if the 13th were spread evenly, each day would get 685.7. The reason is that the 400-year cycle has 146,097 days, exactly 20,871 weeks, so the pattern repeats exactly, and the leap-year rule makes some weekdays slightly more common than others.
What is the longest wait between two Friday the 13ths?
14 months, from a Friday the 13th in one month to the next one more than a year later. The shortest wait is 1 month: February and March of a common year, because February then has exactly 28 days (as in 2026: February, March, November).
How do I find when my birthday next falls on a Friday?
Switch to the second tab: pick the month and day, choose Friday and the first year. For Christmas Day (December 25) the next Fridays after 2025 are 2026, 2037, 2043, 2048, 2054, 2065. The gaps between those years are 5, 6 or 11 years, because the weekday of a date moves ahead one day in a common year and two after February 29, and the pattern repeats exactly every 28 years inside a century without a skipped leap day.
When will February 29 fall on a Friday?
February 29 comes only in leap years, so the weekday cycle is longer: 2036, 2064, 2092 are the next three years starting at 2026. The calculator skips years without a February 29.
Can I check another day, such as Tuesday the 13th?
Yes. Choose any weekday and any day of the month from 1 to 31, and the calculator lists the months and the years. A day of the month that some months lack (the 29th, 30th and 31st) is skipped in the months that do not have it.
How the calculation works
For every month the calculator finds the weekday of the chosen day with the Gregorian calendar rules (a year is a leap year if divisible by 4, except centuries not divisible by 400) and keeps the months where it matches. A year has 52 weeks and one day (two in a leap year), so a date moves forward one weekday per year, two after a leap day. In a common year the 13th of February, March and November always fall on the same weekday, and so do April and July, January and October, and September and December; in a leap year the groups are January, April and July; February and August; September and December; and March with November. That is why one Friday the 13th usually brings others. Over a 400-year cycle, 4800 months produce the weekday counts above.
Worked example: 2026
January 1, 2026 is a Thursday. February has 28 days in 2026, so the 13th of February and the 13th of March have the same weekday; February 13 is a Friday, and so is March 13. November 13 is the third Friday the 13th, as 245 days separate March 13 from November 13 (35 weeks). The calculator finds the same three months directly, February, March, November.
Limits
The calculator uses the Gregorian calendar for every year it accepts, from 1583 on (the first full year after the 1582 reform); it does not reproduce the Julian dates people used before their country adopted the Gregorian calendar (Britain and its colonies switched in September 1752, other countries in other years). Friday the 13th is a superstition, not science, and unlucky days differ from country to country; use the page for fun and for planning. For ordinary business, use the day-of-the-week calculator or the date calculator.
Friday the 13th superstitions are folklore, not science; this page is for fun and for calendar planning. How we check our calculators.
Sources: Gregorian calendar rules (Pope Gregory XIII's bull Inter gravissimas, 1582; leap-year rule: divisible by 4, except by 100 unless by 400); the 400-year distribution of the 13th over weekdays is computed by this page for every month of 2000–2399 and agrees with the table in the Wikipedia article “Friday the 13th” (secondary source, read October 28, 2026). Related: day of the week calculator, nth weekday calculator, leap year calculator, date calculator and calendar.