Golden Ratio Calculator
Apply the golden ratio (φ = 1.6180339887…) to any dimension. Get the golden pair, visualize the Fibonacci spiral, and explore design applications.
φ (Phi) = 1.6180339887…
How to Use the Golden Ratio Calculator
- Enter a dimension — choose whether your value is the larger or smaller dimension of the pair, enter the number, and select a unit (px, em, mm, etc.).
- Click Calculate — the golden pair appears with the Fibonacci spiral visualization showing your dimensions as a golden rectangle.
- Design mode — enter a base value (e.g., 16px font size) to get a full typographic scale and layout dimensions derived from Phi.
- Reference — see all key constants derived from the golden ratio including the golden angle, conjugate, and reciprocal.
What Is the Golden Ratio?
The golden ratio φ (phi) is the positive solution to the equation φ² = φ + 1, giving φ = (1 + √5) / 2 ≈ 1.6180339887. A line segment is divided in the golden ratio when the ratio of the whole line to the larger part equals the ratio of the larger part to the smaller part: (A+B)/A = A/B = φ. This self-similar property makes φ unique — it's the only number where its reciprocal equals itself minus 1: 1/φ = φ − 1 ≈ 0.618.
The Golden Rectangle
A golden rectangle has sides in the proportion 1:φ. Its unique property: remove a square (with side equal to the shorter dimension), and the remaining rectangle is another golden rectangle with the same proportions. This nesting can continue infinitely. Drawing a quarter-circle arc through each successively smaller square's corners traces the golden spiral — a good approximation of the logarithmic spiral (r = ae^(bθ)) found in nature.
Design Applications
Typography: If your body font is 16px, a golden-ratio scale gives headings at 16 × φ = 25.9px, 16 × φ² = 41.9px, etc. Line height: 16 × φ ≈ 26px is often ideal for readability. Column widths: a main content column at 760px paired with a sidebar at 760/φ ≈ 470px creates a golden split. Logo design: placing the focal point at 61.8% of the width and height from the corner places it at the golden point. The iPhone's home button radius, Apple's logo proportions, and Twitter's bird are all frequently cited as using golden ratio geometry.
Golden Ratio in Nature
The golden angle (137.5°, derived from 360°/φ²) explains the spiral arrangement of sunflower seeds, pine cone scales, and leaf placement. When a plant grows a new element at the golden angle offset from the previous one, the result is the most efficient packing — no two leaves ever directly overlap to compete for sunlight. Fibonacci numbers appear because any integer near a Fibonacci number has a Fibonacci number as its nearest golden-angle multiple. See our Fibonacci Generator for the direct mathematical connection.
The Mathematics of Phi
Phi is an algebraic irrational number (root of x² − x − 1 = 0). Its continued fraction is [1; 1, 1, 1, ...] — all ones, making it the number hardest to approximate by a rational fraction (explaining why Fibonacci ratios converge to it slowest of all irrationals). Its powers follow Fibonacci: φⁿ = F(n)φ + F(n−1). It appears in the diagonals of a regular pentagon and in the angles of a regular pentagon (36° and 72° are golden-ratio related). The golden gnomon (the thin triangle in a regular pentagram) has golden ratio sides.