To choose an international shoe size, measure both feet, use the longer foot, and compare that measurement with the exact brand and product size chart. There is no universal US–UK–EU conversion that works for every shoe. Check the chart’s category, measurement labels and width guidance before ordering.
A size conversion helps you select a starting size; trying the shoes on tells you whether their shape suits your feet. Keep your measurements handy, but check the relevant chart whenever you change brands, models or footwear categories.
Table Of Contents
Understanding shoe size systems
US, UK and EU numbers are size labels, not interchangeable measurements. A conversion row describes how a particular chart maps those labels. It does not establish that shoes from another manufacturer with the same number will fit identically.
- US: Confirm whether the listing uses men’s, women’s or children’s sizing.
- UK: Read the UK column in the applicable chart instead of subtracting a fixed amount from every US size.
- EU: Use the brand’s stated equivalent, including any half or fractional sizes it lists.
- CM, JP and CN: Check what the label represents before treating it as measured foot length.
Work across a single chart row. Converting from US to EU on one website, then EU to UK on another, can combine different mappings and produce a misleading result.
Women’s international shoe size conversion
Start with the women’s chart linked to the product. Find your measured foot length using the chart’s instructions, then read across to the size system offered in the ordering menu. If the chart only converts existing sizes, treat your usual size as a starting reference and look for additional measurement guidance.
For a unisex shoe, establish which sizing category the displayed number uses. A listing that shows two size labels should identify what each represents. Avoid assuming a fixed men’s-to-women’s offset applies to every brand. If the product page and chart use different labels, ask the seller to clarify before buying.
Men’s international shoe size conversion
The Nike men’s footwear size chart maps Nike’s US, UK and EU sizes. Use it for the relevant Nike footwear rather than extending its conversions to other manufacturers.
Nike also distinguishes the CM figure printed on a shoe label from measured foot length in centimeters. When selecting by measurement, find the chart’s foot-length information instead of matching your ruler reading to a similarly numbered CM label.
A familiar size from an existing pair can help you compare options, especially when replacing the same model. For a different model, still check product-specific guidance and width availability. A matching length label does not tell you how much space the shoe provides around the forefoot or over the top of the foot.
Children’s shoe sizes: toddler, kids’ and youth charts
Use the chart for the child’s footwear category. Age descriptions can help you navigate a store, but they should not determine the size you buy. Keep any letters or category labels attached to the size; a bare number can be ambiguous when a retailer sells both children’s and adult footwear.
The adidas kids’ shoe size chart directs shoppers to measure both feet and compare the measurements with its own chart. Children’s sizing should be read in the relevant kids’ table rather than inferred from adult conversions.
Measure again before a new purchase instead of automatically ordering the next size. Follow the product’s fitting guidance for toe space, and avoid adding an arbitrary growth allowance to the measurement. During the indoor try-on, check both shoes and ask the child about pressure or slipping.
How to measure both feet
Read the brand’s measuring directions first. If it provides a specific method, follow that method so your measurement matches the chart’s intended input. For a straightforward heel-to-toe measurement:
- Place paper on a firm, level floor and have a ruler and pencil ready.
- Stand with your weight supported normally. Ask someone to help mark the heel and longest toe if bending makes you shift position.
- Measure the straight heel-to-toe distance, keeping the units consistent.
- Repeat for the other foot and record both measurements. Use the longer one when selecting a length.
- Repeat any uncertain reading before comparing it with the chart.
Keep the unrounded measurement until you read the brand’s instructions. If it falls between entries, follow that chart’s advice rather than applying a universal rule to size up or down. Do not add extra toe allowance unless the measuring instructions call for it.
Reading CM, JP and CN labels carefully
Measurement units and shoe-size labels serve different purposes. Converting centimeters to millimeters is straightforward: 24 centimeters equals 240 millimeters. That arithmetic alone does not establish that a shoe marked JP 24, CN 240 or CM 24 fits a foot of that length.
Look for wording that explains whether the number means foot length, a size designation or an internal shoe measurement. An insole length is also a different measurement from the length of your foot. If a seller provides numbers without defining them, request the applicable chart and measurement method.
For specialty footwear using another system, such as a Mondo label on a ski boot, consult the product’s fitting instructions. An everyday shoe conversion is not enough to select specialized equipment.
Check width, socks and toe room
Length is only one part of fit. Check how the manufacturer defines its width options; letters and descriptions should be interpreted within that brand’s chart. Choosing a longer shoe solely to gain width may leave excess space at the front without resolving the pressure across your foot.
- Socks: Try the shoes with the socks you intend to wear, particularly when comparing thin everyday socks with thicker boot socks.
- Toe room: Check for usable space without crowding, following guidance for the specific footwear.
- Heel hold: Walk indoors and notice whether the heel repeatedly lifts or slides.
- Overall shape: Check pressure across the forefoot and over the top of the foot, even when the length seems right.
Athletic shoes, dress shoes and boots do not each follow a universal sizing adjustment. Use model-specific guidance and assess the actual fit. Do not rely on a promise that uncomfortable pressure will disappear with wear.
Buying online and trying shoes indoors
Before paying, confirm the size system in the selection menu and review the seller’s return conditions. Check the return deadline, shipping costs, exchange availability and any restrictions applying to the item. International orders deserve particular attention to the return address and postage requirements.
Customer reviews can flag recurring fit concerns, but comments about running small or large depend on the reviewer’s reference point. Give more weight to reviews that identify the exact model and explain the fit issue.
Try both shoes on a clean indoor surface, following the seller’s rules and retaining packaging and tags as required. Fasten them normally and walk enough to notice pressure or slipping. Ordering two sizes is only practical if the upfront cost and return terms work for you.
Bottom line
Measure both feet, select the correct brand and product chart, and read across its size labels. Then check width, socks, toe room and heel hold during an indoor try-on. Treat international conversion as a starting point, with the return policy providing a practical option if the fit is unsuitable.