Golden Ratio Calculator

How to use

1. 1Pick a mode: Golden split to divide a length, Golden sequence to build a scale, or Check two values to test an existing pair.
2. 2In Golden split, choose whether your number is the whole, the long part, or the short part, then type it to see all three parts and the visual split.
3. 3In Golden sequence, enter a base value and how many steps up and down you want, then read the phi stepped scale and copy the full list.
4. 4In Check two values, type two measurements to see their ratio, how far it is from phi, and the value that would make the pair perfectly golden.
5. 5Use Copy on any row to grab a value, Load example to see a worked split, or Clear to start over.

About this tool

Golden Ratio Calculator works with phi, the irrational constant equal to (1 + the square root of 5) divided by 2, roughly 1.6180339887. Two quantities are in the golden ratio when the larger divided by the smaller equals the whole divided by the larger, and that single property drives every mode in this tool. The first mode splits a length into its two golden segments. Enter the whole and it returns the long part (the whole divided by phi) and the short part (the remainder), so a 1000 pixel width breaks into about 618 and 382. The same mode runs in reverse: give it just the long part and it returns the matching short part and the whole, or give it the short part and it returns the long part and the whole, which is the calculation people reach for when sizing a sidebar against a content column, a heading against body text, or a focal point inside a frame. A live bar shows the split visually with the long segment labelled a and the short segment labelled b. The second mode builds a golden scale: pick a base value and how many steps you want above and below it, and each step up multiplies by phi while each step down divides by phi, producing the kind of modular scale used for type sizes, spacing tokens, and layout rhythm, with a copy button for the whole list. The third mode checks two measurements you already have. It divides the larger by the smaller, reports the exact ratio, shows how far that ratio sits from phi as both a difference and a percentage, and tells you the value that either side would need to be for the pair to be perfectly golden, which is useful when auditing an existing design rather than starting from scratch. Results are reported to several decimal places, the order of the two inputs never matters because the larger value is always divided by the smaller, and a ratio within about one percent of phi is flagged as effectively golden because that is the tolerance the eye reads as balanced. Everything is computed in your browser as you type, so the numbers you enter are never uploaded.

Free to use. Works in your browser. No signup, no login.