Shoe Size Conversion Charts: How to Convert US, UK, EU, and CM
Shoe size conversion is an estimate, not an exact science. If you know your foot length in centimeters, you can use standard international charts and a shoe size converter to estimate your US, UK, EU, CM, and Mondopoint (millimeter) equivalents, then verify the result against the specific brand’s own size chart before buying. There is no single master formula that works across every brand and every shoe model, because regional systems are built on different logic: adult US and UK sizes use one-third-inch steps, EU sizes use Paris-point spacing, and Mondopoint expresses foot length directly in millimeters. The practical answer for online shoppers is to treat any converted number as a starting point, and to treat measured foot length as the most reliable input you can bring to a size chart.
Direct answer and decision summary
The single most important thing to understand is that shoe sizes are labels, not measurements. A "US 9" or "EU 42" label only means something inside the sizing system that produced it. When you cross from one system to another, you are translating between conventions that were never designed to be perfectly interchangeable. According to The Brannock Device Company, the US size system is linear, with each additional full size adding one-third of an inch in length. EU sizes are based on Paris points, so they do not line up cleanly with US half sizes.
That is why the most reliable conversion path runs through foot length rather than through size numbers. Your foot length in centimeters or millimeters is a physical fact; a size number is a regional label. When a product page lists only the size system you do not know, or when you know your measured foot length but not the matching retail label, a converter lets you compare international footwear charts quickly.
A second key point is that conversions are approximate by design. Shoe size conversions are practical estimates because brands, shoe shape, width, socks, and regional charts all affect fit. Different brands use different lasts, toe boxes, and conversion charts. A converter normalizes your input to a shared measurement, then rounds to common half-size labels, but rounding hides the fact that brands disagree with each other at the margins.
The practical decision summary for a shopper is therefore short. First, measure both feet, ideally at the end of the day, and use the larger foot. Second, convert that foot length into estimated US, UK, EU, CM, and Mondopoint values using a standard chart or converter. Third, look up the specific brand’s official size chart and compare your centimeter or millimeter measurement against it, because the general chart is only a reference point. Finally, check the retailer’s return and exchange terms before ordering, since fit risk is real and policies vary by store and destination.
Before going further, it helps to fix a few definitions. CM in shoe sizing usually refers to foot length or insole length in centimeters, depending on the manufacturer. Mondopoint expresses foot length in millimeters, so a Mondopoint value of 270 means a foot length near 270 mm, which is also 27.0 cm. Korean (KR) sizing follows the same logic: it is the foot length in millimeters, making it equivalent to the length component of Mondopoint. Mexican sizing is less consistent; it may correspond directly to foot length in centimeters, or it may roughly align with US men’s sizing, so using your CM measurement is the safest comparison. Chinese (CN) sizing is also inconsistent and may mirror EU sizing or represent foot length in millimeters depending on the product, so the product page or brand chart must be checked.
Key options and criteria
There are two practical approaches to converting shoe sizes, and the criteria for choosing between them depend on what information you actually have.
Option 1: Convert a known size number. If you know your size in one system — say US men’s 10 — a converter can output the estimated US women’s, UK, EU, CM, and Mondopoint equivalents at once. This is fast and useful for scanning overseas listings, but it inherits the error of whichever chart generated your original size. If your US 10 was itself a rough fit, converting it simply spreads the uncertainty.
Option 2: Convert from a measured foot length. This is the more reliable path. Enter your foot length in centimeters or millimeters and let the converter estimate the corresponding labels in each system. Measured foot length is the shared measurement behind adult sizing systems, which is why it produces the best accuracy estimate. Many brands include CM or MM measurements on their official size charts, allowing a more direct comparison than relying on regional labels alone.
When comparing systems, keep these criteria in mind:
- Adult system logic. Adult US and UK sizes use one-third-inch steps, while EU sizes use Paris points. This mismatch is why EU to US conversions rarely land on a clean half size.
- Men’s versus women’s offsets. Common retail charts place US women’s sizes about 1.5 sizes above equivalent US men’s sizes. The standard rule of thumb is US Women’s Size ≈ US Men’s Size + 1.5, though this is a general rule that does not account for width or brand variation.
- Kids’ labels. Children’s shoes move from child "C" labels to youth "Y" labels and should be chart matched rather than converted by formula. Kids mode in a converter typically uses a lookup chart and recommends the next larger row when a measured foot length falls between two entries.
- Width. Width is generally not converted by standard charts, but it can change which size feels comfortable. Width lettering varies: men’s standard or medium is usually "D" (sometimes "M"), women’s standard is usually "B" (sometimes "M"), men’s wide is often "E," "EE," or "EEEE," and women’s wide is often "D," "E," or "EE." If you frequently find shoes tight or loose side to side, look for brands offering width options.
For a quick sanity check, here are representative mid-range values from a standard adult chart. A US men’s 10 is often estimated near EU 44, UK 9.5, and about 27.3 cm of foot length. A US women’s 8 is often estimated near EU 38.5, UK 6, and about 24.5 cm. Treat these as approximations only; the same number does not hold across all brands.
How to check fit, compatibility, or terms
Checking fit before buying is a three-part process: measure accurately, match against the brand’s own chart, and understand the purchase terms.
Step 1: Measure accurately. Precise foot length is crucial for accurate conversion, especially when comparing brands. Use a hard floor, a wall, paper larger than your foot, a pen, and a ruler marked in both centimeters and inches. Place the paper against the wall, stand with your heel firmly against the wall while wearing the socks you would normally wear with the shoes, and have someone trace your foot with the pen held vertically. Measure the straight line from the back of the heel mark to the tip of your longest toe, then repeat for the other foot and always use the longer measurement.
Two refinements matter. First, measure at the end of the day, when feet are likely to be slightly swollen, for the most accurate sizing. Second, account for comfort room: most size charts account for shoe length rather than exact foot length, so unless a brand guide says otherwise, add about 1 cm (roughly ⅜ inch) to your foot measurement before comparing to size charts to allow for necessary wiggle room. As a fit check, ensure there is about a thumb’s width (approximately ½ inch or 1–1.5 cm) of space between your longest toe and the end of the shoe.
Step 2: Match against the brand’s own chart. This is the step most shoppers skip, and it is the one that determines whether the order works. Shoe sizing can vary significantly between brands, so use general converters and charts as a starting point but always check the brand’s official size chart before making a purchase. If a brand lists JP sizing, note that it usually corresponds to CM or Mondopoint, which makes direct comparison easier. Brands known for offering multiple widths, such as New Balance, are generally true to size in length, but a width check is still advisable. Some brands primarily use UK or EU sizing rather than US sizing, so identify the system on the chart before matching your number.
Step 3: Check purchase and return terms. Fit risk is a real cost, and store policies vary by retailer and destination. Delivery timelines, return windows, exchange rules, and whether return shipping is covered differ between stores and regions, and import duties or taxes may apply on cross-border orders. These details are stated on the store’s own policy pages at the time you order, and they can change, so verify them on the store before purchase rather than relying on a general guide. If you are between sizes, the safer direction depends on the shoe type: for athletic shoes or boots, sizing up is often safer, while for some sandals or dress shoes sizing down may be better if the material allows for stretch. Material matters too: leather shoes may stretch slightly, while synthetics usually will not, so factor that into your sizing decision and understand the return policy.
Common mistakes and verification checklist
Most shoe size conversion errors come from a small set of recurring mistakes. Avoiding them is more useful than memorizing charts.
Mistake 1: Trusting a converted number as exact. Shoe size conversions are estimates because brands, shoe shape, width, socks, and regional charts all affect fit. Use the result as a starting point, not a guarantee.
Mistake 2: Measuring only one foot. Most people have one foot slightly larger than the other; always size based on the larger foot.
Mistake 3: Measuring at the wrong time of day. Measure your feet at the end of the day when they are likely to be slightly swollen for the most accurate sizing.
Mistake 4: Ignoring socks and shoe type. Always measure wearing the type of socks you intend to wear with the shoes. Shoe type changes the ideal fit: running shoes might require sizing up about half a size for toe splay, hiking boots need room for thicker socks and foot swelling, and dress shoes often have a snugger fit.
Mistake 5: Forgetting width. Width is not converted by standard length charts, but it can change which size feels comfortable. If standard-width shoes often feel tight or loose, width may be the real problem rather than length.
Mistake 6: Assuming Mexican and Chinese sizes follow one rule. Mexican sizing is highly variable, and Chinese sizing is notoriously inconsistent, so prioritize CM or MM measurements and check the product page or brand chart for clarification.
Mistake 7: Assuming kids’ sizes scale like adult sizes. Children’s sizes are different and should be chart matched; when a measured foot length lands between two entries, the next larger row is usually the practical starting point.
Before you order, run this verification checklist:
- Your foot length is measured in centimeters and inches, using the longer foot, with the socks you plan to wear.
- About 1 cm of comfort room has been added before comparing to the chart, unless the brand says otherwise.
- You have opened the specific brand’s official size chart and matched your CM or MM measurement directly against it.
- You know which sizing system the product page uses — US, UK, EU, CM, or Mondopoint.
- Width has been checked if you commonly need narrow or wide fits.
- The store’s current shipping, duty, return, and exchange terms have been confirmed on the store itself, since these vary and can change.
- If between sizes, you have chosen the direction that matches the shoe type and material.
Frequently asked questions
How accurate is a shoe size converter?
A converter uses standard international conversion data, which is generally accurate for estimating size. However, because brands and even models within a brand vary significantly, it serves as a guideline — always verify with the specific brand’s size chart and measure your foot length in CM, IN, or MM for the best results.
What is the most reliable measurement to use?
Your actual foot length in centimeters or millimeters is the most reliable starting point. Many brands include CM or MM measurements on their official size charts, allowing a more direct comparison than regional sizes like US, EU, or UK.
How does EU shoe size convert to US?
There is no perfect formula, as it differs for men, women, and brands. As very rough guides, men’s US is sometimes approximated as (EU size × 0.75) + 2, and women’s US as EU size − 31, but these are imprecise. Use a converter or chart for better estimates and prioritize the brand’s own chart.
How do I convert US men’s to US women’s sizes?
The standard rule of thumb is US Women’s Size = US Men’s Size + 1.5, and conversely US Men’s Size = US Women’s Size − 1.5. This is a general rule that does not account for width or brand variation.
What do width letters like M, D, B, W, and E mean?
Men’s standard or medium width is usually "D" (sometimes "M"), and women’s standard is usually "B" (sometimes "M"). Men’s wide is often "E," "EE," or "EEEE," while women’s wide is often "D," "E," or "EE." "W" can mean Wide. Narrow widths also exist, such as men’s B and women’s A or AA.
How do Korean and Mondopoint sizes convert?
Korean sizing is the foot length in millimeters and is the same as the Mondopoint length measure. For example, KR 265 = 265 mm = 26.5 cm of foot length. Mondopoint is an international standard based on foot length and width in millimeters, and it is commonly used for ski boots and military boots.
What is the order of kids’ shoe sizes?
Kids’ sizes progress from baby and infant sizes ending in "C," through toddler sizes, up to 13.5C. After 13.5C, the scale switches to youth sizes starting at 1Y and continues upward, and size 1Y is larger than 13.5C.