What is a US size 9 in UK and EU?

A US men's 9 is about a UK 8.5 and an EU 42.5, with a foot length near 27 cm. Women's and kids' charts use different numbers for the same lengths, so always pick the matching chart first.

How do I measure my foot length for CM sizing?

Stand on a sheet of paper with your heel against a wall, mark the tip of your longest toe, and measure heel-to-toe in centimetres. Enter that as the CM value — it is the most brand-independent way to size shoes.

Why are men's and women's sizes different for the same shoe?

They are two numbering scales over the same physical foot lengths. US women's sizes run about 1.5 larger than US men's, so one shoe can carry two different size numbers depending on which chart you read.

How do EU shoe sizes relate to foot length?

EU uses the Paris-point system where each full size is two-thirds of a centimetre (about 6.67 mm) of last length. As a rough guide, EU size is close to your foot length in millimetres divided by 6.67, plus the maker's toe allowance.

How do kids and youth shoe sizes work?

Children's sizes run roughly 0 to 13 (little kid), then restart at 1 for youth/big-kid sizes just above 13. This converter uses the little-kid scale; once a child outgrows US 13 they move onto the youth scale, and a teen near a women's size can use the women's chart.

Should I size up if I am between sizes?

Usually yes. Most people are more comfortable in the larger of two adjacent sizes, especially in closed shoes. Matching the CM (foot length) column rather than guessing a number is the safest approach, since brands run small or large.

Completely. Every conversion runs in your browser using fixed arithmetic — nothing you type is ever sent to a server or stored.

Shoe Size Converter — Gera Tools

A shoe size converter for the systems that matter when you shop across borders: US, UK, EU and CM (foot length), with separate charts for men, women and kids. Type a size you already know into any field and every other system fills in instantly, or use the From/To selectors and the swap button for a focused single conversion. It is built for online shoppers buying from another country, parents sizing children’s shoes, and anyone who wants to turn a measured foot length straight into a buyable size.

How it works

Every sizing system is just a different label applied to one underlying number: your foot length. So the converter resolves whatever you type into foot length in millimetres and fans every other system out from there. Because the focused result, the live cross-fill grid and the reference chart all read from that same anchor, they can never disagree.

The relationships are exact, not guesses:

US and UK use the barleycorn system, where one full size equals one-third of an inch — about 8.47 mm of shoe-last length.
EU uses the Paris-point system, where one full size equals two-thirds of a centimetre — about 6.67 mm.
CM is the Mondopoint label: the number is simply your foot length in centimetres.

Each chart is calibrated to a widely published anchor row. Men’s is fixed at US 9 equals UK 8.5, EU 42.5 and 27 cm. Women’s US runs about 1.5 sizes above men’s for the same foot, anchored at US 7 equals UK 5, EU 38 and 24 cm. Kids use the little-kid scale anchored at US 13C equals UK 12.5, EU 32 and 19.7 cm. If a value implies an unusual foot length for the chosen chart, the tool flags it so you can check you picked the right system.

Worked example

Suppose a US store lists a trainer you like in a men’s US 10.5 and you need the EU number. Select the Men chart, type 10.5 into the US field, and the tool resolves it to a foot length of roughly 283 mm (28.3 cm), then reads across to UK 10, EU 44.5 and CM 28.3. Hit swap and you can go the other way — type the EU number to get back the US size.

US (men)	UK	EU	CM	Foot (mm)
8	7.5	41	26.2	262
9	8.5	42.5	27.0	270
10	9.5	44	27.8	278
10.5	10	44.5	28.3	283
11	10.5	45	28.7	287

Because brand sizing drifts, the most reliable method is to measure your actual foot length and convert from the CM column. Everything is calculated locally in your browser — nothing is uploaded or stored.