Fibonacci Spiral Generator

Free Live preview Client-side

Free Fibonacci spiral generator and golden spiral preview, Fibonacci calculator (F(n) and first-n terms), ASCII art text you can copy, Fibonacci numbers on squares, live φ ratio, colors, and PNG export.

Spiral controls — preview updates live.

More squares → larger Fibonacci sizes.

Fibonacci calculator F(n) & sequence

F1=1, F2=1, …

F12 = 144
ASCII text export

Monospace raster; wider = more detail.

Live preview

Scroll up/down to zoom · Drag to pan · Double-click resets pan · Square sides follow Fibonacci 1, 1, 2, 3, …

ASCII preview (optional)

                

How it works

Fibonacci numbers start with 1, 1, then each term is the sum of the two before: 1, 1, 2, 3, 5, 8, 13, …

Tiling packs squares with those side lengths along a rectangle in a fixed order (add to the right, then below, then left, then above, and repeat).

Spiral In each square, a quarter circle of radius equal to the side length is drawn with its center at the corner nearest the spiral pole (where the first two 1×1 squares meet), so each arc stays inside its square and joins the next; this approximates the golden spiral. Ratios of consecutive Fibonacci numbers approach φ ≈ 1.618.

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