Global Shoe Size Converter

1. Pick the system you know in Convert from: US men, US women, UK, EU, or a foot length in mm, cm or inches.
2. Type the size (such as 9 or 42) or your measured foot length (heel to the tip of the longest toe).
3. Read the equivalent sizes on the top line, then the exact values below to see whether you sit between two sizes.

Here is what each result means:

A shoe size system is a numbered scale that stands for a foot length, with a fixed step between sizes. The main systems use different steps and starting points, which is why the same foot has a different number in each one.

ISO 19407 describes three main systems. Mondopoint, defined in ISO 9407, is the foot length in millimetres, with 5 mm steps for half sizes. The European system, once called Paris points, steps 6.67 mm per size from zero. The UK system steps 8.47 mm, starting at 101.6 mm (4 inches); its 13 children sizes come first, then the count restarts at 1 for adults.

The US system uses the same 8.47 mm step. ISO 19407 notes that in practice it matches UK sizes plus an arbitrary offset of one size for men and usually two sizes for women. That offset is a convention, not a formula, so it varies by brand. China, Japan and the Republic of Korea use Mondopoint for length.

A shoe size is not a measure of width, volume or toe depth. Two shoes with the same number can fit very differently.

It turns any input into a foot length in mm, then turns that length into each size system with the ISO 19407 relationships.

1. Convert the input to foot length. For a UK size, reverse the formula: foot = (UK + 25) x 8.47 - 16.94 mm. For cm multiply by 10; for inches multiply by 25.4 (exact, NIST).
2. Add two size steps to the foot length. ISO 19407 treats the gap between foot and shoe last as about two sizes.
3. Divide by the step for each system, and for UK subtract the 25 steps that come before adult size 0 (12 steps for the 4 inch start plus 13 children sizes).
4. Round to the nearest half size for the top line, and keep the exact values below it.

The mm to cm converter and the inches to mm converter show the length steps on their own.

A shopper wears US men 9 and is buying a shoe labelled in EU sizes.

Step 1: US men 9 is UK 8. Foot length = (8 + 25) x 8.47 - 16.94 = 279.51 - 16.94 = 262.6 mm, which is 26.26 cm or 10.34 in.

Step 2: EU = (262.6 + 13.34) / 6.67 = 41.37, which rounds to EU 41.5. US women = UK 8 + 2 = 10.

Step 3: the nearest Mondopoint step is 265, the label a Japanese or Korean store would use.

What it means: EU 41.37 sits between 41 and 41.5, closer to 41.5. Many brands label this size EU 42, as ISO 19407 itself notes. Try 41.5 first, and keep 42 in mind for a snug style.

The conversion is exact math on foot length. The shoe that fits also depends on these factors.

Brand Grading and Rounding

Makers build shoes on their own lasts and round sizes their own way. ISO 19407 points out that footwear is often labelled 4 UK / 37 EU and 8 UK / 42 EU, half a size above its technical table.

How You Measure

Measure standing, with your weight on the foot, from the back of the heel to the longest toe. Measure both feet, because many people have one longer foot, and use the longer one.

Width and Volume

Size numbers describe length only. A wide or high-volume foot may need a wider fitting or a longer size in a narrow shoe.

Shoe Type

Running shoes, boots and dress shoes use different toe room. Specialist footwear sometimes uses a 7.5 mm Mondopoint step instead of 5 mm.

Each system counts the same foot with a different step and starting point.

Common Adult Sizes by Foot Length

These rows are computed with the formulas above and rounded to half sizes. A brand chart can differ by half a size.

Buying from Another Country

An online store in Europe lists EU sizes, while a US store lists US sizes. Convert your usual size before you order, and read the brand chart too.

Switching Between Men and Women Sizing

Many trainers are sold in unisex or men sizes. The usual rule is US women = US men + 1 for the same foot, because the offsets from UK are 2 and 1.

Starting from a Measurement

Measure your foot in cm and pick Foot length (cm). The rounding calculator helps when a label uses whole or half sizes only.

1. Using the Same US Size for Men and Women

A US women 8 is not a US men 8. The same foot is about a US men 7.

2. Measuring the Old Shoe Instead of the Foot

An insole or outsole is longer than the foot it fits. Enter a shoe length only when the maker states it as last length.

3. Mixing Cm and Mm

A 25 cm foot is 250 mm. Picking mm and typing 25 gives a size far below the adult scale, and the tool warns you.

4. Expecting an Exact Match Between Systems

The steps differ, so whole sizes in one system rarely match whole sizes in another. Check the exact value to see which way to round.

5. Ignoring Width

A longer size can feel roomier in width, but it also moves the flex point of the shoe. A wide fitting is often the better fix.

The foot-length math follows ISO 19407 exactly; the size that fits you still depends on the brand and the shoe.

About EU 42.5. US men 10 is UK 9, a foot length of about 271.0 mm, and (271.0 + 13.34) / 6.67 gives 42.64. Many brands label it EU 43, half a size up.

Subtract 1. The usual offsets are UK + 2 for women and UK + 1 for men, so a US women 8 fits the same foot as a US men 7. Some brands differ.

It means a foot about 27 cm (270 mm) long, the Mondopoint way of labelling used in Japan and elsewhere. That is about EU 42.5, UK 9, US men 10 and US women 11.

No. For adults, US men is usually one size above UK, and US women usually two sizes above UK, for the same foot.

EU steps are 6.67 mm, and brands round and grade from their own lasts. ISO 19407 itself notes shoes labelled 8 UK / 42 EU where its technical table gives 41.5.

Stand on paper with your heel against a wall, mark the tip of your longest toe, and measure in mm. That number is your Mondopoint length.

Not reliably. Children sizes use a separate scale and a toe allowance of 8% of foot length in ISO 19407, and the US offset for children is usually half a size.

About US women 7.5. EU 38 fits a foot of about 240.1 mm, which is UK 5.35, so UK 5.5 and US women 7.5 after the usual two-size offset.

One EU size is 6.67 mm, which is two thirds of a centimetre. One UK or US size is 8.47 mm.

No. Your size and foot length are converted on your device. Pressing Save keeps a copy in this browser only.

• ISO 9407:2019 Footwear sizing, Mondopoint system of sizing and marking (International Organization for Standardization).
• ISO 19407:2023 Footwear, sizing, conversion of sizing systems (International Organization for Standardization).
• ISO 19407:2023 sample pages: Mondopoint, EUR, UK and US system definitions and formulas (ISO preview published by iTeh Standards).
• NIST Guide to the SI, Appendix B.8: inch conversion factor (NIST SP 811).