How many Friday the 13ths does a typical year have?

Usually one to three. Every calendar year has at least one, and the exact count depends on which day of the week January 1st falls on and whether the year is a leap year.

Can I search a single year or a whole range?

Both. Enter a single "YYYY" for one year, or "YYYY-YYYY" for an inclusive range covering multiple years.

Is there a limit on the range size?

Yes, up to 500 years in a single range. Anything larger is rejected with an error asking for a smaller range.

What happens if a year in the range has no Friday the 13th?

That's not possible, every calendar year has at least one Friday the 13th, so the output always includes at least one line per year in the range.

Find Friday the 13th | List every Friday the 13th within a given year or year

Overview

Introduction

Friday the 13th has stuck around in popular culture as an unlucky date, and it's a genuinely interesting bit of calendar trivia: it isn't rare, and it isn't evenly distributed either.

This tool finds every occurrence of it within a year or a range of years, by directly computing the day of the week the 13th falls on in each month.

What Is Find Friday the 13th?

A Friday the 13th finder that scans a single year, or an inclusive range of years, and lists every month whose 13th day lands on a Friday.

It works by checking all 12 months of each year in the range against the calendar's actual day-of-week calculation, not an approximation or a lookup table.

How Find Friday the 13th Works

The input is parsed as either a single four-digit year or a "YYYY-YYYY" range with the start year no later than the end year.

For every year in that range, each of the 12 months is checked by constructing the date for the 13th of that month in UTC and reading its day of the week; whenever that day is Friday, the date is added to the output list.

When To Use Find Friday the 13th

Use it to plan around, or just look up, upcoming Friday the 13ths for a given year.

It's also a handy way to explore calendar patterns, like confirming that some years have three Friday the 13ths while others have only one.

Often used alongside Find What Day of the Week July 4th Falls On, Validate a Calendar Date and Find Day of the Year.

Features

Advantages

Computes the day of the week directly from calendar math instead of a hardcoded table, so it works correctly for any year, past or future.
Accepts both single years and multi-year ranges in one input.
Uses UTC internally so results aren't affected by the browser's local timezone or daylight saving transitions.

Limitations

Capped at a 500-year range per run to keep results manageable.
Only reports the Gregorian calendar's Friday the 13th occurrences; it doesn't account for other calendar systems.

Examples

Finding every Friday the 13th in 2026

Input

Output

2026-02-13
2026-03-13
2026-11-13

Checking all 12 months of 2026 against Friday, only February, March, and November have a 13th that falls on a Friday.

Finding Friday the 13ths across a range

Input

2027-2028

Output

2027-08-13
2028-10-13

Each year in the range is checked independently, and every matching date across both years is listed together in chronological order.

Best Practices & Notes

Best Practices

Use a single-year search when you just need to plan around the current or next year's occurrences.
Use a multi-year range to spot patterns, like how often a year has more than one Friday the 13th.

Developer Notes

The day-of-week check is `new Date(Date.UTC(year, month0, 13)).getUTCDay() === 5`, run across `month0` from 0 to 11 for every year in the parsed range; using `Date.UTC` avoids any local-timezone or DST edge cases that could otherwise shift a date across a day boundary.

Find Friday the 13th Use Cases

Checking whether an upcoming year has an unusually high or low number of Friday the 13ths
Planning event scheduling around a superstitiously significant date
Exploring calendar trivia or building a themed date-based feature

Common Mistakes

Entering a range larger than 500 years, which is rejected; split a very large range into smaller batches instead.
Assuming the count is the same every year; the number of Friday the 13ths in a given year can be one, two, or three depending on how the calendar falls.

Tips

Pair this with July 4th Weekday Finder if you're exploring other day-of-week calendar patterns for a range of years.
A year with a Friday the 13th in February is guaranteed to also have one in March, since February and March always start three days apart in a common year, and the same three-month spacing recurs elsewhere in the calendar.

Find Friday the 13th