Shoe Size Converter API Reference

Overview

Shoe Size Converter works by converting the input size to centimeters as a base measurement, then calculating equivalent sizes in all supported regions. Returns conversions for all international standards simultaneously.

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

GEThttps://api.apiverve.com/v1/shoesizeconverter

curl "https://api.apiverve.com/v1/shoesizeconverter?size=9&from=us&gender=men" \
  -H "x-api-key: your_api_key_here"

const res = await fetch('https://api.apiverve.com/v1/shoesizeconverter?size=9&from=us&gender=men', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

import requests

res = requests.get(
    "https://api.apiverve.com/v1/shoesizeconverter?size=9&from=us&gender=men",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/shoesizeconverter?size=9&from=us&gender=men", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Parameter	Type	Description
`size`Required	string	The shoe size to convert
`from`Required	string	Source region `usukeucmjpaumxkr`
`gender`Optional	string	Gender sizing `menwomenunisexchild` default unisex

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "input_size": 9,
    "input_region": "US",
    "gender": "men",
    "conversions": {
      "cm": 29.1,
      "jp": 29.1,
      "us": 9,
      "uk": 8.1,
      "au": 8.1,
      "eu": 43.7,
      "mx": 13.7,
      "kr": 43.7
    },
    "note": "Sizes are approximate and may vary by manufacturer"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`input_size`	number	`9`	The size that was supplied
`input_region`	string	`"US"`	Sizing system the input was given in
`gender`	string	`"men"`	Gender sizing used for conversion
`conversions`	object	`{...}`	The equivalent size in every supported sizing system
`cm`Premium	number	`29.1`	Size in centimeters
`jp`Premium	number	`29.1`	Japanese shoe size
`us`	number	`9`	US shoe size
`uk`	number	`8.1`	UK shoe size
`au`	number	`8.1`	Equivalent Australian size
`eu`Premium	number	`43.7`	EU shoe size
`mx`	number	`13.7`	Equivalent Mexican size
`kr`	number	`43.7`	Equivalent Korean size, in millimetres
`note`	string	`"Sizes are approximate and may vary by manufacturer"`	Caveat that sizes are approximate and vary by manufacturer

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted	A key restriction or IP allow-list; see key scoping.
`429`	Rate limited, or out of credits	Read `error` to tell them apart; see rate limits.

Use cases

E-commerce: Help international customers find their correct shoe size when shopping from different countries
Travel Planning: Convert shoe sizes when shopping abroad or purchasing from international retailers
Size Charts: Generate comprehensive size charts for footwear products with multiple regional standards
Retail Apps: Integrate size conversion features into shopping apps to improve customer experience

Other ways to use Shoe Size Converter

Set up Shoe Size Converter on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →

Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →

Shoe Size Converter