Enter a length or dimension (in any unit). The tool multiplies and divides it by phi (1.618) to give you the two golden ratio pairs.
Enter a positive number for the base dimension.
Enter two dimensions (for example the width and height of a photo or a layout) to see how close their ratio is to the golden ratio.
Enter two positive numbers to compare.
What is the golden ratio and why 1.6180339887
The golden ratio, written as the Greek letter phi, is an irrational number that begins 1.6180339887 and never repeats or terminates. It comes from dividing a line into two parts so that the ratio of the whole line to the larger part equals the ratio of the larger part to the smaller part. That single property is what gives the ratio its reputation for feeling balanced: the same proportion repeats at every scale, from the whole shape down to its smallest division.
Golden ratio examples in British design and architecture
The Parthenon in Athens is the example most often quoted worldwide, though closer to home the golden ratio has a long history in the UK print trade: pre-digital typesetters used printed proportion charts and golden section dividers to lay out book pages and advertisements well before desktop publishing existed. In contemporary web and editorial design, UK studios still reach for a 1.618 grid as a quick way to size a sidebar against a main column, or to set the crop of a hero photo without measuring by eye. Some British logo designers also build wordmarks and icon grids on golden proportions to give a mark a sense of underlying structure.
Limits of the golden ratio
The golden ratio is not a magic formula that guarantees good design, and its presence in historic art and architecture is genuinely debated among art historians. Several well-known claims, that particular paintings, buildings or even human faces were built deliberately around phi, have been challenged or shown to rely on selective measurement, where a rectangle is drawn to fit the argument after the fact rather than measured first. Treat the ratio as one compositional option among several, not as proof that a design is objectively correct.
Formula and practical use in web and print design
The formula is simple: if you have one dimension, multiply it by phi (about 1.618) to get a larger complementary dimension, or divide it by phi to get a smaller one. In web design this can set a sidebar width against a main content column, or the height of a hero image against its width. In print, it can define page margins or the relationship between a page's width and height. Apply the larger and smaller values from this calculator directly in your layout software, or use the Image Cropper to test a golden-ratio crop on a photo, then switch to the second mode above to check how close an existing design already sits to the golden ratio.