If you are looking for the most pleasing proportion between two things you should start with the golden ration (they can be anything from paddings on websites to proportions of buildings). In UX design we can live with the rough estimate of 1.618 for this irrational number.
Golden ratio is the mean that is the most pleasing to the eye. It is found in many works of fine arts, architecture, but also in case of natural objects, and even abstract concepts like stock market analysis. Two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one. (a+b)/a = a/b = ϕ [phi]
Getting You to the Greek
Golden ratio is also called “mean of Phidias”, after the Greek sculptor, famous for creating the statues of the Parthenon (He lived more than 400 years before Christ). And popularized by another Greek: Euclid. The „father of geometry” gave the first known definition of the golden mean: A straight line is said to have been cut in extreme and mean ratio when, as the whole line is to the greater segment, so is the greater to the less.
Mathematically the golden ratio is an irrational number: (1+5^(1/2))/2
Truth to be told in most cases 1.6 is a fair estimate, but with computers it is quite easy to use 1.618. You could go to quite a few more digits, like 1.618033988749894848204586834365638117720309179805762862135… but in realty 1.6180 is more than enough.
The beauty of the golden ratio is that even if you want to use its inverse (1/ϕ, or ϕ^-1) you will get a number smaller by one. So 1/ϕ = ϕ-1 ≈ 0.618.
In the next article about golden ratio we will look into usage scenarios, and some quick and dirty ux design recipes that are based on the mean of Phidias.