You find the perfect blazer from a French boutique. The shoes? Italian leather, listed as “EU 42”. Your favorite Japanese brand runs in centimeters. And somewhere between a US 8 and a UK 10, you’ve probably guessed — and guessed wrong. Size conversion shouldn't be a gamble. Whether you're shopping cross‑border or just tired of returns, understanding international sizing is the secret to a seamless wardrobe.
I built this tool because I was tired of squinting at tiny size charts that never matched. SizeFlow converts clothing and shoe sizes between over 30 international units — instantly, accurately, and completely free.
Women's, men's & kids' — dresses, jeans, shirts, shoes, even ring sizes.
US, UK, EU, JP, AU, KR, CN and many more — every system you'll encounter.
No signup, no clutter — just pick category, enter size, see all equivalents.
Works offline — once loaded, it's in your pocket forever.
Whether you're ordering Italian leather boots, a Japanese kimono, or British denim, SizeFlow.io gives you the numbers you need in seconds. No more returns, no more guesswork.
Try SizeFlow now →Used by thousands of global shoppers every day
Now that you know where to get exact conversions, let's understand why sizes differ so wildly in the first place. Because once you see the logic, you'll shop with real confidence.
There’s no universal standard. A US women’s 8 is roughly a UK 10, an EU 38, and a Japanese 11 — but vanity sizing, brand quirks, and even the type of garment shift the numbers. Men’s shirts? A 15.5" collar in the US might be labeled 39 in Europe (centimeters) and “M” in Asia. And let’s not start on kids’ sizes.
Shoes are even trickier: a US men’s 9 equals a UK 8, EU 42, and about 27 cm in Japan. But the difference between a US women’s 8 and a men’s 7 is just 1.5 sizes — and many unisex sneaker brands use men’s sizing as default. It’s no wonder that nearly 30% of online clothing returns are due to poor fit.
| US | UK | EU | IT | JP |
|---|---|---|---|---|
| 4 | 8 | 34 | 40 | 7 |
| 6 | 10 | 36 | 42 | 9 |
| 8 | 12 | 38 | 44 | 11 |
| 10 | 14 | 40 | 46 | 13 |
| 12 | 16 | 42 | 48 | 15 |
While memorizing a few benchmarks helps, you don't need to keep a cheat sheet. SizeFlow's converter covers dresses, jeans, shoes, rings, and more — from US/UK/EU to Australian, Chinese, and even Korean sizes. You enter what you know, and it returns every equivalent. It’s like having a multilingual tailor in your pocket.
1️⃣ Choose category (women's shoes, men's shirts, etc.)
2️⃣ Pick your known size and its country
3️⃣ Instantly see every international equivalent.
Works on phone, tablet, desktop — no download needed.
European shoe sizes are based on the “Paris point” (⅔ cm), while the UK and US systems use barleycorn increments. That’s why a EU 42 is not exactly a US 9 — it’s closer to a 9.5 in some brands. And if you’re buying from Japan, you’ll see the foot length in centimeters (e.g., 27.0 cm). SizeFlow shows you the precise foot length alongside the sizes, which is a lifesaver for online sneaker drops.
| US | UK | EU | CM (JP) |
|---|---|---|---|
| 8 | 7 | 41 | 26 |
| 9 | 8 | 42 | 27 |
| 10 | 9 | 43 | 28 |
| 11 | 10 | 44 | 29 |
Again, brands differ: an Italian 43 might be a US 10, but a French 43 is often a US 9.5. The easiest way to avoid the headache? Use SizeFlow before you hit “buy”.
Three seconds to clarity
I keep SizeFlow.io bookmarked on my phone. While I’m in a fitting room abroad or browsing a European boutique online, I just tap, convert, and know exactly what fits. No more “maybe it’ll stretch”.
Even with perfect size conversion, remember that a French 38 in a tailored blazer fits differently than a slouchy linen dress. Always check the garment measurements if available (chest, waist, length). And when in doubt between two sizes? The converter can't tell you that — but it can at least give you the correct starting point.
One more thing: shoe width matters. US sizes often come in narrow (B), medium (D), wide (2E). European sizing is usually a standard width, but you might see “G” for wide in UK. SizeFlow includes width notes for many categories.
Bookmark SizeFlow.io — it’s free, fast, and covers more units than any department store chart.
You can find the full conversion suite at sizeflow.io — yes, it’s that straightforward. No ads, no clutter — just the numbers you need, in every unit imaginable.
— never guess your size again.