How to Convert Shoe Sizes Between US, UK, EU, and CM

If you have ever tried to buy shoes from an international retailer, you know the frustration of staring at a size chart and having no idea which size to pick. US, UK, EU, and CM — every region has its own system, and none of them align cleanly with the others. This guide breaks down how each system works, why they differ, and how to convert between them accurately.

The good news is that once you understand the logic behind each system, converting between them becomes straightforward. The better news is that you can skip all the math and use our shoe size converter to do it instantly.

Why Shoe Sizes Differ by Country

Shoe sizing was never standardized globally. Each country developed its own system based on local measurement units and manufacturing traditions. The US system evolved from the English system but diverged into separate scales for men, women, and children. The UK system is rooted in the barleycorn unit (one-third of an inch), dating back to medieval England. The EU system uses Paris Points, a metric-based unit where each size represents two-thirds of a centimeter. And the Mondopoint system (CM) is the simplest of all — it is just your actual foot length in centimeters.

Because these systems were developed independently, there is no clean mathematical formula that perfectly converts between all of them. Conversion charts are based on empirical measurements and manufacturer data, and there is always some approximation involved. That said, the conversions are accurate enough for practical purposes — usually within a half-size of the correct fit.

The Major Sizing Systems

US Sizes

The US system uses separate scales for men, women, and children. A US men’s 10 is different from a US women’s 10, even though they may correspond to the same physical shoe size in other systems. The system starts at size 1 for infants and goes up from there, with a transition point between child and adult sizing.

US sizing is the most common system in North America and is used by most American and Canadian shoe brands, including Nike, New Balance, and Converse. Many international brands also include US sizes on their labels alongside EU or UK sizes.

UK Sizes

The UK system is based on barleycorns, an old English unit equal to one-third of an inch. A child’s size 0 starts at 4 inches (the length of a newborn’s foot plus some growing room), and each subsequent size adds one barleycorn. Adult sizes continue from where children’s sizes leave off.

The UK system is used in the United Kingdom, Ireland, Australia, New Zealand, and South Africa. Unlike the US system, UK sizes are the same for men and women — a UK 8 is the same physical size regardless of who is wearing it, though the styling and fit may differ.

EU Sizes (Paris Points)

The EU system, also called Paris Points, measures the length of the shoe’s last (the mold the shoe is built around) in a unit called a Paris Point, which equals two-thirds of a centimeter. The system is unisex — there is no separate men’s or women’s scale.

EU sizes are used throughout continental Europe, most of Asia, and many other regions. They are the most widely used system globally. A typical adult range runs from EU 35 (small adult) to EU 47 (large adult).

CM / Mondopoint

The Mondopoint system (ISO 9407) is the international standard for shoe sizing. It uses the actual length of the foot in millimeters or centimeters, measured from heel to the longest toe. This is the most intuitive system because the size directly corresponds to foot length.

Mondopoint is widely used in Japan, China, and for military and industrial footwear. It is also the system used by most athletic shoe manufacturers for internal sizing, even when they label their shoes in US or EU sizes. If you know your foot length in centimeters, you have the most reliable starting point for any shoe size conversion.

Men’s vs Women’s Size Differences

The most confusing aspect of shoe sizing is the gender split in the US system. A US men’s 8 and a US women’s 8 are not the same shoe. As a general rule, a women’s US size is about 1.5 sizes larger than the equivalent men’s size. So if you wear a US men’s 8, you would wear roughly a US women’s 9.5.

In the UK system, the difference is about 1 to 1.5 sizes. A UK men’s 8 is roughly equivalent to a UK women’s 9 or 9.5. The EU system does not differentiate between genders at all — an EU 42 is the same regardless of whether the shoe is marketed to men or women.

Keep in mind that women’s shoes are often built on a narrower last than men’s shoes of the same size. This means that even if you convert sizes correctly, the fit may feel different due to width and arch support differences. Some brands offer unisex models that use the same last for both genders.

Kids’ Shoe Sizing

Children’s shoe sizing is a bit more complex because it varies by system. In the US, kids’ sizes start at infant sizes (often labeled as 0-3 months, 3-6 months, etc.) and then transition to numbered toddler sizes (1-13), followed by youth sizes (1-7). The number restarts after size 13, which means a “youth 3” is not the same as a “toddler 3.”

In the EU system, there is no restart — sizes simply increase with foot length. A child with a 20 cm foot wears EU 32, regardless of whether they are classified as a toddler or youth. This makes the EU system easier to use for children’s shoes.

Children’s feet grow rapidly, especially in the first three years. A toddler may go through 3 to 4 shoe sizes per year. Pediatricians and podiatrists recommend checking children’s shoe size every 2 to 3 months and ensuring about 1 cm of growing room at the front of the shoe. Shoes that are too small can cause foot problems, while shoes that are too large can cause tripping and poor gait development.

Why You Should Measure Your Feet

Many people wear the wrong shoe size without realizing it. A study published in the Journal of Foot and Ankle Research found that up to 70% of people are wearing incorrectly fitted shoes. This can lead to blisters, bunions, calluses, and long-term foot problems.

To measure your foot accurately, stand on a piece of paper with your heel against a wall. Trace the outline of your foot (or have someone do it for you) and measure from the heel edge to the longest point, which is usually the big toe or second toe. Measure both feet, as they are often slightly different sizes, and use the larger measurement. Do this in the evening, when your feet are at their largest.

Once you have your foot length in centimeters, you can use the Mondopoint system as a universal reference. This measurement is more reliable than trying to convert between US, UK, or EU sizes, because it represents an actual physical dimension rather than an abstract number on a brand-specific scale.

Tips for Buying Shoes Online

Buying shoes online can be tricky, especially when shopping from international retailers. Here are some practical tips to improve your chances of getting the right fit:

• Start with your foot length in centimeters. This is the most universal measurement and can be used with any size chart.
• Check the specific brand’s size chart. Brand-to-brand variation can be significant. Nike, Adidas, and New Balance all size differently from each other.
• Read reviews about fit. Look for reviews that mention whether the shoe runs large, small, true to size, or wide/narrow.
• Consider width in addition to length. Standard sizes assume a medium width. If you have wide or narrow feet, you may need to adjust your size or look for width-specific models (2E, 4E, etc.).
• Understand the return policy. Make sure the retailer accepts returns on worn shoes (many do for sizing reasons) or offers free exchanges.
• Order from retailers with free shipping both ways. This removes the risk of being stuck with the wrong size.
• Use a conversion tool. Our shoe size converterhandles the math for you and supports men’s, women’s, and kids’ sizes across all four major systems.

Frequently Asked Questions

How do I convert US men’s to US women’s shoe sizes?

As a general rule, add 1.5 to your US men’s size to get the equivalent women’s size. So a men’s US 8 would be approximately a women’s US 9.5. This is an approximation and may vary slightly by brand, so always check the specific brand’s size chart when possible.

Are EU sizes the same worldwide?

In theory, yes. The EU (Paris Points) system is a standardized measurement. In practice, there can be slight variations between manufacturers, just as with any sizing system. An EU 42 from one brand may feel slightly different from an EU 42 from another brand due to differences in last shape, padding, and intended fit.

What size is 27 cm in US shoe size?

A foot length of 27 cm corresponds to approximately US men’s 10, UK 9, or EU 44. For women, 27 cm is roughly US women’s 11.5 or EU 44. These are approximate conversions — use our shoe size converter for precise results.

Do shoe sizes change as you age?

Yes. Your feet can continue to change size well into adulthood. Weight gain, pregnancy, aging (which can cause arches to flatten), and certain medical conditions can all affect foot size. It is a good idea to measure your feet every year or two, especially if you notice your shoes feeling tight or uncomfortable.

How do half sizes work?

In the US system, each full size represents about one-third of an inch (one barleycorn). A half size adds half of that increment, or about one-sixth of an inch. In the EU system, full sizes are 6.67 mm apart, and half sizes are 3.33 mm apart. Not all brands offer half sizes in all styles.

What if I am between two sizes?

If you are between sizes, the general advice is to size up rather than down. Shoes that are slightly too large can be adjusted with thicker socks or insoles, but shoes that are too small will cause discomfort and potential foot problems. However, if you have narrow feet or are buying performance footwear (running shoes, cycling shoes) where a snug fit matters, you may prefer to size down.

Related Calculators

• Shoe Size Converter — Convert between US, UK, EU, and CM sizes
• Unit Converter — Convert between units of length, weight, and more