Shoe Size Conversion Calculator

Background.

A shoe size conversion calculator estimates US, UK, and EU shoe sizes from a single, reliable measurement: foot length in centimeters, heel to longest toe. This calculator deliberately starts from length rather than from a size you already 'know,' because length is the one measurement that translates across borders and brands — a size label does not. The US shoe-sizing system itself is built around exactly this idea: the Brannock Device, invented in 1925 and still the standard foot-measuring tool used in shoe stores across the United States, measures foot length directly and converts it to a size using a fixed rule the Brannock Device Company states plainly on its own site: a men's US size 1 corresponds to a foot length of 7 and 2/3 inches, and each additional whole size adds exactly 1/3 of an inch.

The honest complication, and the reason this page leads with heavy caveats rather than a single definitive table, is that shoe sizing genuinely is NOT one universal system. It differs by gender (women's US sizes are conventionally about 1.5 sizes larger in number than the men's size for an identical foot length), by country (the UK uses its own numeric scale, historically built on the same one-third-inch step as the US but starting from a different reference point), and critically by manufacturer and shoe last (the internal mold a shoe is built around). Two different brands' 'size 9' can fit noticeably differently because their lasts are shaped differently, even when both brands nominally target the same foot length. The international standards community has tried to solve this with the Mondopoint system — ISO 9407 defines footwear sizing directly by millimeter foot length rather than by any national numbering convention — precisely because a length-based measurement is the one thing that doesn't drift between brands the way a size label does.

This calculator's EU-size estimate is the least precise of the four figures it returns, and it says so. Continental European shoe sizing traces back to the 'Paris point,' a unit equal to two-thirds of a centimeter that French shoemaking guilds standardized in the early 1800s specifically to reduce sizing chaos across manufacturers. The EU formula here approximates that system, but real brand charts routinely diverge from any single formula by a full size or more once you compare two specific companies' actual products. The right way to use this calculator is as a fast, sensible starting point before you order online — not as a guarantee. If a purchase is expensive, non-returnable, or a gift for someone whose foot you can't measure directly, cross-check the specific brand's own published size chart, which is the only chart that reflects that brand's actual lasts.

What is shoe size conversion calculator?

Shoe size is a numeric or alphabetic label assigned to a shoe based on the foot length (and sometimes width) it is designed to fit, but unlike a metric measurement, the label itself is not standardized internationally — the same physical foot length maps to a different number under the US system, the UK system, and the EU (Continental) system, and even within one country's system, a men's and a women's shoe of 'the same' foot length carry different numeric labels by convention. The most length-based and internationally recognized alternative is ISO 9407's Mondopoint system, which sizes footwear directly by millimeter foot length rather than by any national numbering scheme, specifically to give manufacturers and consumers a common reference point that doesn't require guessing which country's chart applies.

This calculator takes your foot length in centimeters — the most reliable, brand-independent measurement you can take at home — and estimates US (both men's and women's conventions), UK, and EU sizes from it using published sizing conventions, including the Brannock Device Company's own stated rule for US men's sizing. Every output is explicitly labeled an estimate, because sizing in practice varies by brand, by shoe last, and sometimes by shoe style within the same brand.

How to use this calculator.

1. 01Stand up and measure your foot from the back of your heel to the tip of your longest toe, in centimeters — ideally at the end of the day, when feet are typically at their largest.
2. 02Measure both feet; most people have one foot slightly longer than the other. Use the longer measurement.
3. 03Enter that length in centimeters.
4. 04Read the estimated US men's size (primary result), alongside the estimated US women's, UK, and EU sizes.
5. 05Treat the EU figure as the roughest of the four estimates — always check the specific brand's own size chart before ordering, especially for a first purchase from that brand.
6. 06If you're between two sizes, most footwear guidance recommends sizing up rather than down, since a slightly loose shoe (fixable with a thicker sock or insole) is more comfortable than a slightly tight one.

The formula.

The calculator first converts your entered centimeter length to inches (dividing by 2.54), because the Brannock Device Company's own published sizing rule is stated in inches: a US men's size 1 corresponds to a 7-and-2/3-inch foot, with each whole size adding exactly 1/3 inch. Rearranging that rule algebraically gives usSizeMens = 3 × footLengthIn − 22, which reproduces the Brannock reference points exactly (7.667 inches gives size 1.0; 10.333 inches gives size 9.0).

The US women's estimate adds 1.5 to the men's figure, an industry-convention offset consistent with data points from at least one major footwear brand's own published conversion practice (a UK 7 corresponding to a men's US 8 or a women's US 9.5, and a EU 42 corresponding to a men's US 8.5 or a women's US 10 — both differ by exactly 1.5). The UK estimate subtracts 0.5 from the men's US figure, reflecting that both the historical US and UK systems are built on the same one-third-inch step (the 'barleycorn') but start counting from different reference points; UK adult shoe sizing is presented here as a single numeric scale, the common retail convention, though not a universal rule.

The EU estimate is the least precise of the four and is labeled as such throughout this page. It approximates the Continental European 'Paris point' system, in which 1 point equals 2/3 of a centimeter — a unit French shoemaking guilds standardized in the early 1800s. The formula used here, euSize ≈ 1.5 × footLengthCm + 2, folds in a small allowance for manufacturing toe-room before converting centimeters to points. Real brand charts can diverge from this formula by a full size or more: for a 26cm foot, one major brand's own published chart lists EU 41.5, while this page's formula (applied to a very similar 25.4cm length) gives EU 40.1 — a meaningful gap that illustrates exactly why the EU figure should be treated as a rough starting estimate, not a final answer.

A worked example.

Frequently asked questions.

References& sources.

1. [1]The Brannock Device Company, About Us — the standard foot-measuring tool for the footwear industry, and the source of this calculator's US men's length-to-size rule ("a Men's size 1 is 7-2/3 inches; each additional size is 1/3 inch longer").
2. [2]ISO 9407:2019, Footwear sizing — Mondopoint system of sizing and marking. International Organization for Standardization.
3. [3]ISO 19407:2023, Footwear — Sizing — Conversion of sizing systems. Provides conversion tables between the Mondopoint, European, UK, US, Chinese, Japanese, and Korean shoe-sizing systems, based on foot length. International Organization for Standardization.