SamCalculator

Shoe Size Conversion Calculator

Convert shoe sizes instantly between US, UK, EU, India, Japan, China, and international sizing systems with smart fitting recommendations and foot-length analysis.

Conversion Mode5 modes · switch anytime

Convert between US, UK, India, EU, Japan, Mexico, and China for men and women.

Enter a size or foot length above to see every international conversion.

Why shoe sizes don't match across countries

There is no single global shoe-size system. A US 9 is a UK 8 is an EU 42 is a Japanese 27 cm — all describing the same foot. Each country built its scale around different reference points: the US used to count in barley-corns starting at a child's foot, the UK uses 1/3-inch increments from a fixed origin, the EU divides shoe length by 6.67 mm (the historic Paris Point), and Japan/Mexico use the foot length itself in centimetres (the Mondopoint system). Add to that the fact that every brand builds shoes around its own last — a foot-shaped wooden mould — and the same number can fit very differently across two brands. This converter normalises everything to foot length in millimetres so you get an accurate cross-system match in one click.

How Shoe-Size Conversion Works

1. Normalise to foot length

Every size scale maps mathematically to a foot-length range in millimetres (the Mondopoint reference). The converter first turns your input into mm using the source country's formula.

2. Re-derive every other system

From that single foot-length value, the calculator outputs the equivalent on US Men, US Women, UK, India, EU, Japan, Mexico, and China scales — rounded to the nearest half-size.

3. Apply gender & width offset

US men's and women's scales are offset by 1.5 sizes. Wide and narrow feet adjust the comfort recommendation up or down by half a size.

4. Brand-specific correction

Each brand has a known last-size offset. Brand Comparison mode applies that offset so a Nike 9 maps correctly to a Vans 8.5 or a Converse 8.

6 Real-Life Ways to Use This Converter

1

Online Shopping

Verify your size before clicking 'add to cart' on an international site (ASOS UK, Zalando EU, Rakuten JP).

2

Sneaker Reselling

Resell platforms list in multiple regional sizes — quickly confirm a US 10 = UK 9 = EU 44.

3

Travel Shopping

Bought a pair in Italy or Japan? Convert the label to your home country's size before you fly back.

4

Kids School Shoes

Convert the EU size on the school list to the US/UK number stocked at your local store.

5

Sports & Running

Performance shoes typically run small — use the converter plus foot-length input to upsize by half.

6

Luxury & Italian Brands

Italian leather brands frequently size half-to-one number small — confirm with the brand comparison panel.

Best Practices for Measuring Your Foot

✓

Measure at the end of the day

Feet swell up to 1 cm between morning and evening. The most accurate measurement is the largest one.

✓

Wear your normal socks

Thick athletic socks add 2–4 mm of effective foot width. Measure with the same sock you'll wear with the shoe.

✓

Stand, don't sit

Bearing weight elongates the foot by 5–8 mm. A seated measurement undersells your real shoe size.

✓

Use the larger foot

Up to 70% of people have asymmetric feet. Size to the longer foot and pad the smaller side if needed.

✓

Trace, don't tape-measure

Tracing with a vertical pencil captures the longest toe more accurately than a flexible tape that curves around the foot.

✓

Round up, never down

A 24.8 cm foot rounds to size 25, not 24.5. Too short causes black toenails; too long is easily fixed with an insole.

Why Sizing Right Matters

Wearing a shoe one size too small for a year tightens the toe box enough to cause hammer toes, bunions, and ingrown nails — all of which can require surgery. One size too big causes blisters, plantar fasciitis from over-pronation, and chronic ankle instability. The American Podiatric Medical Association estimates that 88% of women and 66% of men wear shoes that are the wrong size, almost always smaller than measured. A 60-second conversion check before checkout is the cheapest podiatric care money can buy.

Online return rates for incorrectly sized shoes are roughly 30% across major retailers. Sizing right the first time saves shipping cost, reduces packaging waste, and means you actually get to wear the shoe instead of repackaging it for return.

Tricky Cases the Calculator Handles

Half-sizes between countries

A US 9 falls between EU 42 and 42.5. The calculator rounds to the closer half-size and notes the in-between fit.

Unisex sneakers (Converse, Vans)

Both labels typically use the men's number; women should subtract 1.5 from the label to get their US Women's equivalent.

Children crossing C → Y sizes

US children's sizing switches from 13C to 1Y at foot length ≈ 210 mm. The label changes but the foot size does not.

Wide / narrow lasts

Two shoes labeled '9' from different brands can have a 6 mm width difference — the calculator's width recommendation accounts for this.

Japanese cm sizes

Japan often lists half-cm sizes (24.5, 25.0, 25.5). Mondopoint-style sizing means the number is the actual foot length in cm.

EU 'cm' converter confusion

Some EU brands print a 'cm' value on the box — that's the shoe last length, ~1 cm longer than the foot. Don't confuse it with the Japan cm size.

Core Conversion Formulas

US Men ↔ Foot length (mm)

US Men = (foot_mm − 220) ÷ 8.4667 + 4

Each whole US size = 1/3 inch = 8.4667 mm of foot length.

UK / India ↔ US Men

UK = US Men − 1 · India = UK

The Indian shoe-size standard is identical to the British one.

EU (Paris Points)

EU = (foot_mm + 15) ÷ 6.6667

EU sizes measure the shoe last, which is about 15 mm longer than the foot; each Paris Point = 2/3 cm.

Japan / Mexico (Mondopoint cm)

JP = MX = foot_mm ÷ 10 (rounded to 0.5 cm)

Mondopoint sizes ARE the foot length in centimetres — the cleanest, most logical system in use today.

Common Sizing Mistakes

!Trusting a label across brands

A 'size 9' from one brand is not a 'size 9' from another. Always check the brand's published last length, or use the Brand Comparison mode.

!Ignoring the gender offset

US men's and women's scales are offset by 1.5 sizes. A women's 8.5 is NOT the same as a men's 8.5 — it's a men's 7.

!Measuring while seated

A seated foot is 5–8 mm shorter than a standing foot. Always measure standing with full weight on both legs.

!Buying for current foot, not finished foot

Running shoes stretch ~3 mm after break-in. Dress shoes can shrink ~2 mm if leather dries out. Match shoe type to your purpose.

!Sizing two feet to the smaller one

Most people have a 3–6 mm foot-length asymmetry. Always size to the longer foot — the shorter one can be padded; the longer one cannot be amputated.

How this calculator is built

All conversions run client-side using the published Mondopoint reference and standard Paris-Point arithmetic. The same formulas are used by ISO 9407, Brannock devices, and major shoe retailers. Brand offsets are derived from publicly documented brand size guides (Nike Run Club, Adidas size chart, New Balance width grading). No data leaves your browser; conversions are instant and reproducible.

Frequently Asked Questions

Different countries use different sizing systems that all describe the same physical foot length. The most common families are US/Canada (men and women use slightly different scales), UK/India (one unified scale roughly 1.5 numbers smaller than US men's), EU and Mexico (Paris Points — about 6.67 mm per size starting from a fixed origin), Japan and Korea (foot length in centimetres rounded to half-sizes), and China (a mix of Mondopoint cm and EU). Conversion is done by mapping a chosen size to a reference foot length in millimetres and then reading the equivalent number on every other scale.

EU sizing is based on the historical Paris Point, where one size equals two-thirds of a centimetre (~6.67 mm). It measures the length of the shoe last (not the foot), so a true EU 40 corresponds to a foot of roughly 25–25.5 cm, allowing about 1 cm of wiggle room. There is no separate men's and women's EU scale — the number is the same — but the underlying last shape (width, toe box, arch) is gendered.

Stand on a piece of A4 paper with weight evenly distributed, in the socks you plan to wear with the shoe. Trace around the foot keeping the pencil vertical. Measure the longest distance from heel to longest toe (often the second toe) in centimetres or inches. Always measure both feet at the end of the day — feet swell up to 1 cm — and use the longer foot.

Yes — India follows the British (UK) shoe-size system, where each whole size equals roughly 8.46 mm of foot length and the scale starts at a fixed reference. A UK 9 is the same physical size as an Indian 9. UK/India sizes are usually about 1.5 numbers smaller than US men's and 0.5 smaller than US women's for the same foot length.

A 'size 9' is not a measurement — it's a label assigned to a manufacturer's specific last (the foot-shaped mould the shoe is built around). Lasts differ in width, toe box volume, arch height, and length tolerance. Nike often runs a half-size small, Adidas Originals run true to size, New Balance often runs slightly wide, and luxury Italian dress brands frequently run a full size small versus US labels.

In US/Canada the women's scale is offset 1.5 sizes higher than the men's scale for the same foot length — so a US men's 7 is a US women's 8.5. UK, EU, India, and Japan use a single unisex number. When converting unisex sneakers (e.g., Converse, Vans) note that the men's number is the canonical one and women should subtract 1.5.

The conversion uses the widely accepted Mondopoint reference where every size on every chart maps to a defined foot-length range in millimetres. Real-world fit is then offset by brand last shape, foot width, sock thickness, and instep height — which is why the recommendation panel suggests up to ± half a size for narrow or wide feet.

Standard guidance is 6–10 mm of space (about a thumb's width) between the longest toe and the front of the shoe when standing. Running shoes benefit from a full 10–12 mm because feet lengthen on impact. Dress shoes can run 5–7 mm tighter. Children's shoes should leave 12–17 mm of growth room — but never more than that.

Up to 70% of people have feet that differ in length by 3–6 mm. Always size to the larger foot and use thicker socks, an extra insole, or a heel grip pad on the smaller side. If the difference is more than 1 cm (one full size), consider buying half-pairs from brands that support split-size orders.

Children's sizing is split into Infant/Crib (0–12 months, EU 16–19), Toddler (1–4 years, EU 20–27), and Big Kids / Youth (5–12 years, EU 28–35). Children's feet grow about half a size every 2–3 months until age 4 and every 4–6 months between 4 and 12, so always check fit monthly and leave 12–17 mm of growth room.

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