Clothing size converter
A US women's 8 is a UK 12 and an EU 38. Enter a size and its system to get the matching US, UK, EU and S/M/L labels from a fixed international chart, for women's dresses and tops or men's jackets and shirts. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Size
- M
- Source size system: alpha
- alpha
- Garment chart: women
- women
- Alpha
- M
- Us
- 8–10
- Uk
- 12–14
- Eu
- 38–40
Shopping across borders means juggling three numeric size systems plus the casual S/M/L labels on tags and product pages. A US women's 8 is not a UK 8, and an EU 38 sits closer to a UK 10 than many shoppers expect. This clothing size converter takes one size label, the source system, and an optional garment chart, then returns the matching US, UK, EU, and alpha (S/M/L) equivalents from a fixed international ready-to-wear table.
How clothing size systems relate and what to send
Ready-to-wear clothing is labeled in several parallel systems. Alpha sizes (XXS through 3XL or 4XL) are letter codes shared on casual tops and tees. United States women's dress sizes are even numbers such as 0, 2, 4 through the mid-twenties.
United Kingdom dress sizes run higher for the same body (a common mapping is UK equals US plus four). European sizes for women's garments typically increase by two per step and sit near the thirties and forties for everyday fits. Men's jackets and shirts often use chest-based numbers where US and UK share the same figure and the EU chest size is roughly ten higher.
Because a bare number like ten is ambiguous without a region, this converter requires both size and system. Optional garment selects the women's dresses and tops chart (default) or the men's jackets and shirts chart. Send size as a string such as M, 8, or EU 38; system as alpha, us, uk, or eu; and garment as women or men when you need the other chart.
Prefixed labels like US 8 are accepted and stripped.
Shopping, online stores and the limits of size charts
Call the free in-browser clothing size converter for travel packing lists, thrift flips, and quick tag checks without installing a spreadsheet of charts. Pair results with product copy that still asks shoppers to check brand size guides, because vanity sizing and stretch fabrics move real fit even when the letter or number matches. Keep inputs on the published chart steps; half sizes, vanity codes like 00 with odd house scales, and children's wear are out of scope for this adult ready-to-wear table.
Authors shipping SDKs can map the matches array into comparison tables that show US, UK, EU, and S/M/L columns side by side—the same layout shoppers expect on international size charts.
What you can do with it
Cross-border product pages
Marketplaces convert a seller's US dress size into UK, EU, and S/M/L labels so international buyers see familiar numbers next to the listing without leaving the page.
Inventory and catalog normalization
Import pipelines normalize mixed supplier size strings into a common US/UK/EU/alpha shape before search filters and recommendation models run.
FAQ
What happens if the size label is unknown?
Labels that are not on the selected garment chart—or systems and garments that are not recognized—are rejected and not charged.
Why is system required for numeric sizes?
A bare number such as 10 means different fits in the US, UK, and EU charts. Requiring system keeps conversions unambiguous and deterministic.
Is the clothing size converter free?
The browser tool runs free on your device.
Do brands always match these numbers?
No. Charts are conventional ready-to-wear approximations. Brand vanity sizing, stretch, and cut still affect fit; use the note field and brand guides when precision matters.
What is a women's M in US, UK and EU sizes?
A women's M covers US 8 to 10, UK 12 to 14 and EU 38 to 40. Because one letter spans two numeric steps, the converter shows the whole band instead of picking an arbitrary midpoint.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/conv/clothing-size \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"size":"M","system":"alpha"}'const res = await fetch("https://api.kit.forhosting.com/conv/clothing-size", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"size": "M",
"system": "alpha"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/clothing-size",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"size": "M",
"system": "alpha"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/clothing-size", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"size":"M","system":"alpha"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"size":"M","system":"alpha"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/clothing-size", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"size": "M",
"system": "alpha"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.clothing_size",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
The path is pure deterministic lookup—no network, no model, no brand API—so the same input always yields the same JSON for checkout UIs, marketplace listings, and style guides. Unknown size labels fail with invalid_input and are not charged.
How clothing size systems relate and what to send
The engine never invents a half-step that is not on the published table: if the label is missing, you get invalid_input instead of a silent guess.
Reading the response: equivalents, ranges, and matches
When a single chart row matches—for example a specific US 8—you receive one numeric equivalent per region and a single alpha letter. When an alpha label spans two numeric steps, such as M covering US 8 and 10 on the women's chart, the numeric fields become inclusive range strings like 8–10 so shoppers see the full band rather than an arbitrary midpoint. On success the response echoes size, system, and garment, then exposes alpha, us, uk, and eu fields that mirror the nested equivalents object. The matches array lists every discrete row that hit, each with alpha, us, uk, and eu integers for pipelines that need machine-friendly numbers without parsing en-dashes. primary always holds the first match for simple UIs that only display one line. match_count reports how many rows contributed. method is always clothing_size_chart, and note reminds readers that brand fit and vanity sizing still vary. Validation failures—missing size or system, unknown system names, unknown garment names, alpha labels on a numeric system, or sizes absent from the chosen chart—raise invalid_input with a message that names the problem, and those requests are not billed after rejection.
API usage, pricing, storefront workflows, and practical limits
Post JSON with required string fields size and system, plus optional garment defaulting to women.
Integration use cases
Checkout and size-guide widgets
Storefronts call the free browser tool or prepaid API to power interactive size charts that map a shopper's home size to the brand's tagging system in real time.
Technical questions
How do I convert a clothing size with this tool?
Send JSON with size (for example M or 8) and system (alpha, us, uk, or eu). Optionally set garment to women or men. The response returns US, UK, EU, and alpha equivalents.