Fibonacci Day
11/23 — the first four digits of the famous sequence (1, 1, 2, 3).
1 min read · Fact-checked · Updated for 2026
About Fibonacci Day
Fibonacci Day is celebrated on November 23rd because the date written as 11/23 forms the first four numbers of the Fibonacci sequence: 1, 1, 2, 3. The sequence, introduced to Europe by Leonardo of Pisa in 1202, appears throughout nature — in sunflower spirals, pinecones, and nautilus shells — and connects to the golden ratio that has fascinated mathematicians and artists for centuries.
Read more on WikipediaWhen is Fibonacci Day?
Fibonacci Day is celebrated every year on November 23. Upcoming dates:
| Year | Date | Day of week | |
|---|---|---|---|
| Fibonacci Day 2026 | November 23, 2026 | Monday | View date → |
| Fibonacci Day 2027 | November 23, 2027 | Tuesday | View date → |
| Fibonacci Day 2028 | November 23, 2028 | Thursday | View date → |
| Fibonacci Day 2029 | November 23, 2029 | Friday | View date → |
| Fibonacci Day 2030 | November 23, 2030 | Saturday🎉 weekend | View date → |
How to Celebrate Fibonacci Day
- 🎯Watch a documentary or read an article connected to Fibonacci Day.
- 💡Visit a museum, planetarium or observatory — many hold events on this day.
- 📣Share a mind-blowing fact with #FibonacciDay.
Official hashtag: #FibonacciDay
Frequently Asked Questions
When is Fibonacci Day 2026?
Fibonacci Day 2026 is on Monday, November 23, 2026.
How many days until Fibonacci Day?
There are 133 days until Fibonacci Day (November 23, 2026).
What category is Fibonacci Day?
Fibonacci Day is categorized as a Science event.
Is Fibonacci Day a public holiday?
Fibonacci Day is an observance day, not typically a public holiday. Check your country's official calendar for local public holidays.
More Science Days
International Day of Women and Girls in Science
February 11
A UN day promoting full and equal access and participation of women and girls in science, technology, engineering, and mathematics.
Pi Day (3.14)
March 14
Celebrated on 3/14 to match the first digits of π (3.14159…), Pi Day honors mathematics with pie-eating contests, math challenges, and classroom fun.
World Meteorological Day
March 23
Marking the founding of the WMO — the science of weather, climate and water.
International Day of Human Space Flight (Yuri's Night)
April 12
Marking Yuri Gagarin's 1961 flight — the day humanity first left the planet.