Fibonacci Calculator

The Fibonacci sequence: 1, 1, 2, 3, 5, 8, 13, 21... Each number is the sum of the two before it.

What this calculator does

F(10) = 55. F(20) = 6,765. The ratio of consecutive Fibonacci numbers approaches the golden ratio φ ≈ 1.618.

Frequently asked questions

What is the 20th Fibonacci number?

F(20) = 6,765.