The golden ratio, denoted by the Greek letter phi, equals approximately 1.6180339887. Two quantities are in the golden ratio if their ratio equals the ratio of their sum to the larger quantity: (a+b)/a = a/b = phi. This unique proportion appears throughout nature (spiral shells, flower petals, leaf arrangements), art (Renaissance compositions, the Parthenon), and modern design (logos, typography, layouts). It is considered aesthetically pleasing and has fascinating mathematical properties.
Phi = (1 + sqrt(5)) / 2 approximately 1.618. 1/phi = phi - 1 approximately 0.618. phi^2 = phi + 1 approximately 2.618. The Fibonacci sequence ratios (1,1,2,3,5,8,13,...) converge to phi. Adjacent Fibonacci numbers approximate the golden ratio increasingly well: 8/5=1.6, 13/8=1.625, 21/13=1.615, approaching 1.618...
Enter a value to find its golden ratio pair (multiply by phi for the larger, divide by phi for the smaller). Or enter two values to check how close they are to the golden proportion. The calculator also generates golden rectangles and spirals based on your input dimensions.
Nautilus shells, sunflower seed spirals, hurricane formations, galaxy arms, flower petal counts (often Fibonacci numbers), pine cone scales, and branching patterns in trees all approximate the golden ratio.
Designers use it for pleasing proportions: page layouts, logo dimensions, typography (font size ratios), image cropping, and spacing. The golden rectangle (sides in ratio 1:1.618) is considered visually harmonious.
The ratio of consecutive Fibonacci numbers converges to phi. As numbers increase, F(n+1)/F(n) approaches 1.618... This connection means Fibonacci spirals approximate golden spirals.