Shoe Size Converter: US, UK, EU, and CM Sizing Explained
Shoe size scales differ by country because they were built around different base units and different average foot-length assumptions, not because one country's feet are systematically different from another's.
EU sizing is the most directly tied to physical measurement — it's roughly based on foot length in centimeters (multiplied by a scaling factor called the Paris point), which is why EU sizes step up in more granular increments than US or UK sizes. US and UK sizing both use their own numeric scales with a roughly consistent but not identical offset from each other (US sizes typically run about 1 to 1.5 sizes larger than the equivalent UK number).
Measuring Foot Length Properly
The most accurate measurement is taken standing (not sitting, since the foot lengthens slightly under body weight), at the end of the day when feet have had time to swell to their daily maximum, measuring from heel to the tip of the longest toe — which is not always the big toe.
Measure Both Feet
Most people have one foot very slightly larger than the other. Sizing shoes to the larger foot avoids a tight fit on that side, even if it means a marginally looser fit on the smaller foot.
Width Is a Separate Dimension
Length-based size charts say nothing about width, which is why the same labeled size can fit well in one brand's wider last and feel tight in another's narrower one — width sizing (narrow, medium, wide) exists specifically to address this, though many brands don't offer it.
Frequently Asked Questions
Why does the same labeled size fit differently between brands?
Shoe size labels only describe overall length on that brand's specific last (the foot-shaped mold used to build the shoe), not width or volume, so two brands using the same size number can differ meaningfully in fit depending on how generously or narrowly each last is shaped.
Should I size based on my longer or shorter foot?
Size to the longer foot — most people have a small natural length difference between feet, and a shoe sized to the shorter foot risks being uncomfortably tight on the longer one, while sizing to the longer foot only means a very slightly looser fit on the other side.
How does shoe width factor into size charts?
Standard size charts describe length only; width is a separate measurement (often labeled narrow, medium, or wide) that not all brands offer. If a shoe consistently feels tight across the widest part of your foot despite correct length, a wider width option — where available — is usually the fix rather than sizing up in length.
Is EU sizing based on foot length in centimeters?
Approximately — EU sizing is derived from foot length using a scaling factor historically called the Paris point, which is why EU sizes increase in smaller, more granular steps than the US or UK scales for the same underlying length change.
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