Fibonacci Day 1421

Fibonacci Day uses the month and day notation 11/23 to echo the opening numbers of the Fibonacci sequence: 1, 1, 2, 3.

Frequently asked questions

When is Fibonacci Day 1421?

Fibonacci Day 1421 is on Friday, 23 November 1421.

What day of the week is Fibonacci Day 1421?

It falls on Friday.

How is Fibonacci Day calculated?

This event is observed every year on 23 November.