Shoe Size Converter: US, UK, EU & International Size Chart
Shoe sizes vary dramatically between countries — a US men's size 10 is a UK size 9.5 and a European size 43. When shopping online from international brands or preparing for travel, knowing your correct size in different systems prevents costly returns and uncomfortable fits. Our Shoe Size Converter instantly converts between US, UK, EU, and Japanese sizes for men, women, and children, with foot length measurements in centimeters.
International Shoe Size Systems
The US shoe sizing system differs for men and women — a US women's size 8 is roughly equivalent to a US men's size 6.5. UK sizes are typically 0.5 to 1 size smaller than US men's sizes. European sizes use a continuous scale based on the Paris point (2/3 cm increments) and do not distinguish between genders — a EU size 42 is the same for men and women. Japanese sizes use centimeters of foot length directly. The conversion is not always exact because each country uses different last lengths and width allowances. Always measure your foot length in centimeters for the most accurate conversion — this calculator uses foot length as the reference standard to minimize sizing errors.
How to Measure Your Foot Size
Stand on a piece of paper with your heel against a wall. Mark the longest toe's position and measure the distance in centimeters. Measure both feet, as one foot is usually slightly larger — buy shoes for the larger foot. Measure your feet at the end of the day when they are slightly swollen from walking. Wear the type of socks you will wear with the shoes when measuring. Add 0.5-1 cm of extra length (called "wiggle room") for comfort and to account for foot swelling during activity. Children's feet grow quickly and should be remeasured every 2-3 months. Using this converter with your actual foot measurement in centimeters gives the most reliable size across all international sizing systems.
How the Conversion Formulas Work
The converter is built on a set of linear formulas that map each sizing system to foot length in centimeters, then back out to the target system. For men's sizes, US-to-centimeters is US size multiplied by 0.847 plus 19.0, while the UK-to-centimeter formula uses the same slope with a different intercept of 19.8. European sizes convert to centimeters with a different shape entirely: EU size minus 2, divided by 1.5, which reflects the Paris point system of two-thirds of a centimeter per size step. Moving in the opposite direction, the EU size for any foot is foot length in centimeters multiplied by 1.5 plus 2.
Working through a real example shows how these fit together. A US men's size 11 converts to 28.3 centimeters using the men's US formula. From that centimeter value, the UK size is 28.3 minus 19.8, divided by 0.847, which works out to about UK 10, and the EU size is 28.3 times 1.5 plus 2, which rounds to EU 44. The same foot therefore wears a US 11, a UK 10, or an EU 44 depending on which system the brand lists.
Women's sizing uses a different intercept because the US women's scale starts at a lower baseline. A US women's size 8 converts to about 24.5 centimeters, which maps to a UK 5.5 and an EU 39. The converter switches these formulas automatically based on the gender you select, so a men's 8 and a women's 8 never mix. Children's sizes use separate formulas with a shallower slope: US children's sizes convert as US times 0.667 plus 7.5, while UK children's sizes use 0.667 plus 8.0, because children's feet grow in smaller increments than adult lasts.
Common mistakes to avoid when converting shoe sizes:
- Using the adult formula for children's shoes. Child sizing scales differently, so applying the men's or women's formulas can be off by two or three sizes.
- Comparing US men's and US women's numbers directly. They use different baselines, so the same numbered size fits a completely different foot.
- Assuming EU sizes come in half steps. EU sizing uses whole-number increments of two-thirds of a centimeter; half sizes are uncommon, and the converter rounds converted results to the nearest half size for readability.
- Ignoring the rounding step. A conversion like UK 10.06 displays as UK 10, not as a long decimal, so expect whole or half values in the result.
- Skipping the centimeter check. When a size chart lists only foot length, convert that measurement to centimeters first and use it as your anchor across all systems.
Related Calculators
Use our Height Calculator for related body measurements. The Weight Converter converts between pounds and kilograms. Our Length Converter handles all distance unit conversions including centimeters to inches.
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Written by the CalcMaster Pro Editorial Team — financial, health, and DIY tools reviewed for accuracy. All calculators run on standard, widely accepted formulas. Always confirm final numbers with a qualified professional for decisions that require official figures.