Once you know your size, the next challenge is making sense of the different systems. Between UK sizes, EU sizes and US sizes, or others like JPN, Brazil, converting between them can feel more complicated than it should, especially when you are buying online or across different brands.
Why There's No Universal System
The reason shoe size conversion feels confusing is that there's no single global standard. Different countries developed their own systems at different times, and brands build on top of those systems using their own production methods. A shoe marked as a certain size in the UK doesn't always correspond exactly to the same number somewhere else.
The Main Systems
The UK sizing system runs from children's sizes (0 upward) through to adult sizes, which restart at 1 after children's sizing ends around 13.5. Each increment represents roughly one-third of an inch.
The US system follows a similar structure but a different scale, which means a UK to US shoe size conversion isn't always a direct match.
The EU system is based on the length of the shoe's internal mould, increasing in increments called Paris points, roughly two-thirds of a centimetre each. Working out UK to EU shoe size conversion is one of the most common searches when buying from European brands, and it's rarely as intuitive as it looks.
There's also Mondopoint, which measures the actual dimensions of the foot in millimetres. It's precise, but used mainly in sport footwear rather than everyday styles and does not represent the internal length of a shoe.
Why the Same Number Fits Differently
Even within the same sizing system, two shoes at the same size can feel completely different. That's down to the last, the mould each brand uses to shape a shoe. Some are narrower, some wider. Some have more room at the toe, others don't. The last determines the character of the shoe as much as the design does.
Materials matter too. Leather tends to soften and adapt slightly over time. Synthetic materials hold their original shape more firmly. Both affect how a shoe feels after the first few wears. That is worth thinking about when you're deciding between them.
Why This Matters When Your Size Is Hard to Find
Understanding sizing systems matters more when the range of available options is narrower. For anyone shopping in a size 9 or above as a teenager, fit can't be assumed just from the number. Knowing how sizing works across systems and how much it can vary between brands makes it considerably easier to find something that actually works. For a full conversion table, see our manufacturer's sizing guide.
FAQ: Shoe Size Systems
Q What is the difference between UK and EU shoe sizes?
A UK and EU shoe sizes use completely different scales. EU sizes are based on Paris points, roughly two-thirds of a centimetre, while UK sizes increase in increments of approximately one-third of an inch. A UK 6, for example, is roughly an EU 39, but because the scales don't align perfectly, always check the specific brand's conversion chart rather than assuming a standard offset.
Q How do I convert UK shoe sizes to US sizes?
A For women's sizing, US sizes typically run about 1.5 sizes larger than UK, so a UK 6 is roughly a US 8.5. For men, the difference is usually 1 size. That said, brands vary, and some use their own internal conversion methods. If you're buying online, the brand's own size guide is always the most reliable reference.
Q Why do shoes feel different even in the same size?
A The fit is shaped by the last, the mould each brand uses during production. Two shoes marked as the same size can have different widths, toe room, and arch shapes depending on the last. The material also plays a role: leather tends to mould slightly over time, while synthetics hold their original shape. So two shoes in the same size, from different brands or in different materials, can feel noticeably different.
Q What is Mondopoint, and do I need to know about it?
A Mondopoint measures foot length in millimetres rather than using an index number. It's used mainly in specialist sporting footwear, ski boots and some military footwear, rather than in everyday fashion shoes. For most everyday or teen shoe shopping, you won't encounter it.
Q Do teen shoe sizes follow the same system as adult sizes?
A In the UK system, children's sizes run from 0 upward and end around 13.5, at which point UK adult sizing restarts from 1. Teenage girls shopping in size 9 or above are technically in the adult sizing system, even though those shoes were designed for adult women. That mismatch in proportions and styling is part of why the fit often feels wrong.
Q Is a UK7 the same as EU40?
A Usually close, but not always exact. Standard conversion charts put UK 7 at EU 40-41, depending on the brand. Because EU sizing is based on Paris points and UK sizing on a different incremental system, the numbers don't translate perfectly. Use the conversion as a starting point, and check the individual brand's chart for a precise match.