About SIZE ATLAS
SIZE ATLAS is a free converter that translates shoe, clothing, ring and children's sizes across many countries' systems at once. It is made for moments like shopping abroad, browsing shops while traveling or choosing a gift, when you wonder ‘what is this number in my size?’
All calculations happen inside your browser. The foot length and body measurements you enter are not sent to a server, and no sign-up is required.
Main features
- Shoes: convert between Korean mm, Japanese cm, Chinese 码, Mondopoint, EU, UK and US men's and women's sizes. Enter your foot length to see the reference size, the Mondopoint label and advice about foot width.
- Clothing: convert men's tops, suits and bottoms and women's tops, dresses and bottoms across KR, US, UK, EU, IT, FR and JP. Calculates recommended sizes for each system from your chest, waist and hip measurements.
- Bras: calculates band and cup from underbust and bust and converts them to KR, JP, EU, FR, IT, UK and US.
- Rings: convert between Korean sizes (ho), Japanese 号, US, UK/Australian letters and European (ISO 8653) sizes. Find a size by circumference or inner diameter, and see an actual-size circle drawn on a screen calibrated with a credit card.
- Kids: children's shoe (C/Y) and clothing (height-based) sizes, with approximate ages.
- Everywhere: cm/inch unit switch, full chart view, copy results, 11 languages.
How to use
- Choose Shoes, Clothing, Rings or Kids from the tabs at the top.
- In ‘Convert a size’, select the system and size you know, and the sizes in the other systems appear immediately.
- If you don't know your size, enter your foot length or body measurements in ‘Find by measurements’. The result is also applied to the converter.
- Open ‘Show full chart’ to see the complete conversion chart with the current size highlighted.
- Use ‘Copy’ on a result card or ‘Copy all results’ to paste the results into a note or messenger.
Frequently asked questions
The conversion is half a size off from the label on my shoes. Is it wrong?
In most cases it is not an error but a difference in how the systems are converted. US, UK and European sizes are based on the length of the shoe last, and brands differ in toe allowance and rounding, so half-size differences are common. Give priority to the size chart based on foot length (cm) of the brand you are buying. The reasons are explained in Shoe size systems by country.
Which standards do you follow?
For shoes, the foot-length-based systems (KS M 6681, JIS S 5037, GB/T 3293.1, ISO 9407) and the common practice of sportswear brand size charts; for clothing, KS K 0050/0051, ASTM D5585-11e1, the German/French/Italian size rules and JIS L 4005; for bras, EN 13402 and the Korean and Japanese cup steps; for rings, ISO 8653, the US formula, BS 6820 and the Japanese size definition. Each size chart page lists its sources and the date they were last checked.
Are the Korean ring sizes accurate?
The Korean jewelry industry generally uses the same numbers as Japanese sizes (inner diameter 13 mm = size 1, 1/3 mm steps), but we could not confirm a single official standard. Sizes can differ by about one number between shops, so also check the circumference (mm).
The ring circle drawn on screen is not the actual size.
The number of pixels in 1 mm differs from device to device. In ‘Screen calibration’, hold a credit card (85.6 mm wide) against the dashed box and adjust the slider until the widths match, and the circle will be close to actual size. The calibration is saved on that device only.
Are the measurements I enter saved or sent anywhere?
No. All calculations are done inside the browser. Only the unit setting, screen calibration and theme are saved on this device; the measurements you enter are not saved.
Can I rely on the sizes by child's age?
Ages are approximations based on the middle of growth records. Children vary a lot, so always choose sizes by measuring foot length and height yourself. They do not replace growth or development assessments or a diagnosis.