Shoe Size by Foot Length Calculator

How it is calculated

The foot length is converted to each system with its own linear formula. The EU size adds a fixed allowance to the foot length and scales it, and the US and UK sizes count in thirds of an inch.

EU = (L + 1.5) × 1.5

US men = 3 × in − 22, US women = 3 × in − 21, UK = 3 × in − 23, where in = L ÷ 2.54

L is the foot length in centimetres, measured from the heel to the tip of the longest toe, and in is the same length in inches. Each US or UK size step is therefore one third of an inch. All four sizes are shown to 1 decimal and are not rounded to a half size. Only lengths from 19.5 to 35 cm are accepted; shorter or longer values show no result, which keeps the US and UK numbers from going negative. The result does not include shoe-style allowances.

Common mistakes

• Measuring the shoe or the outside of the foot instead of the foot itself. Measure heel to tip of the longest toe, standing, on paper.
• Entering the length in millimetres (260) or inches. The field is centimetres, and 260 is outside the 19.5 to 35 cm range, so no result appears.
• Measuring only one foot. Feet often differ, so use the longer one.
• Treating the output as exact for every brand. Brands and shoe shapes differ, and a size like 8.7 has to be rounded to a real size in the brand's chart.
• Mixing men's and women's US sizes. The two scales differ by one full size, so check which row you are reading.