Golden Ratio Calculator

Calculate golden ratio segments, verify proportions, and explore the divine proportion

Calculate Golden Ratio

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Enter the total length

Golden Ratio (φ)

φ = (1 + √5)/2 ≈ 1.6180339887
The ratio where a/b = (a+b)/a = φ

Results

Error
Whole segment must be positive

Fibonacci Sequence Approximation

The golden ratio appears as the limit of consecutive Fibonacci number ratios:

F(16)/F(15) = 987/6101.6180327869Δ: 0.00000120
F(17)/F(16) = 1597/9871.6180344478Δ: 0.00000046
F(18)/F(17) = 2584/15971.6180338134Δ: 0.00000018
F(19)/F(18) = 4181/25841.6180340557Δ: 0.00000007
F(20)/F(19) = 6765/41811.6180339632Δ: 0.00000003

Golden Ratio Facts

Mathematical Value

φ = (1 + √5)/2 ≈ 1.618033988749...

Greek Letter

Denoted by φ (phi), named after sculptor Phidias

Unique Property

φ² = φ + 1 and 1/φ = φ - 1

Fibonacci Connection

Limit of Fₙ₊₁/Fₙ as n approaches infinity

Applications

Art & Architecture

Parthenon, Mona Lisa, modern designs

Nature

Flower petals, pinecones, shell spirals

Photography

Composition, rule of thirds alternative

Finance

Fibonacci retracements in trading

Tips & Usage

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Golden rectangles can be subdivided infinitely

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Tolerance for verification is ±0.001

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Used in design for aesthetically pleasing proportions

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Appears in pentagon geometry and regular star

Understanding the Golden Ratio

Mathematical Definition

The golden ratio occurs when a line segment is divided into two parts such that the ratio of the longer part to the shorter part equals the ratio of the whole segment to the longer part.

Formula Derivation

If a > b > 0, then:

a/b = (a+b)/a = φ

Solving: φ² - φ - 1 = 0

φ = (1 + √5)/2

Unique Properties

  • φ² = φ + 1 (only positive number where this is true)
  • 1/φ = φ - 1 ≈ 0.618 (golden ratio conjugate)
  • φ = [1; 1, 1, 1, 1, ...] (continued fraction)

Historical Significance

Ancient Greece

Euclid described the "extreme and mean ratio" around 300 BCE

Renaissance

Called "Divine Proportion" by Luca Pacioli (1509)

Modern Era

Term "golden ratio" first used by Martin Ohm (1835)

Geometric Constructions

Golden Rectangle

Rectangle with aspect ratio φ:1

  • • Can be subdivided into smaller golden rectangles
  • • Contains golden spiral when squares are removed
  • • Found in art, architecture, and design

Golden Triangle

Isosceles triangle with golden ratio proportions

  • • Base to side ratio is φ
  • • Appears in regular pentagon
  • • Self-similar when subdivided

Real-World Examples

Architecture

Parthenon facade, UN Building, modern skyscrapers

Art

Mona Lisa composition, Dalí's paintings, photography

Nature

Nautilus shells, sunflower seeds, tree branching