Fibonacci Calculator
Generate Fibonacci numbers and the golden ratio
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
F(n)—
F(n-1)—
F(n+1)—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- n = 12 → F(12) = 144; sequence 0,1,1,2,3,5,8,13,21,34,55,89,144; ratio ≈ 1.617978
- 20th Fibonacci number → F(20) = 6,765 (previous 2,584, next 10,946)
Formula
F(0)=0, F(1)=1, F(n)=F(n−1)+F(n−2). The ratio F(n)/F(n−1) approaches the golden ratio φ = (1+√5)/2 ≈ 1.618034.
About Fibonacci Calculator
Generate Fibonacci numbers and the golden ratio. This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is this tool free to use? +
Yes, it is completely free with no registration or download required.
Is my data private? +
Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.
Does it work on mobile? +
Yes, it works on any device — phone, tablet, or desktop.