Friday the 13th finder
Choose a start and end year up to 100 years apart to see when Friday the 13th comes, for planning events or out of curiosity.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter from year and to year.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
The 13th is a Friday when the month starts on a Sunday. We check the 13th of every month in the range and get its weekday from the days since 1970-01-01 mod 7.
Example
Inputs: From year = 2,026, To year = 2,030. Result: Fridays the 13th: 9; First in the range: Friday, February 13, 2026 (2026-02-13).
Limits and caveats
- The range is capped at 100 years at a time so the table stays readable.
Questions about this tool
How often does Friday the 13th happen in a year?
At least once and at most three times in every Gregorian year.
Why is it tied to months starting on Sunday?
The 13th is 12 days after the 1st, one week and five days, so when the 1st is a Sunday the 13th is a Friday.
How many are there in 2026?
Three: 13 February, 13 March and 13 November 2026.