Unit Converter API
Unit Converter is a simple tool for converting units. It returns the converted value.
The Unit Converter API provides reliable and fast access to unit converter data through a simple REST interface. Built for developers who need consistent, high-quality results with minimal setup time.
To use Unit Converter, you need an API key. You can get one by creating a free account and visiting your dashboard.
GET Endpoint
https://api.apiverve.com/v1/unitconverterCode Examples
Here are examples of how to call the Unit Converter API in different programming languages:
curl -X GET \
"https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg" \
-H "X-API-Key: your_api_key_here"const response = await fetch('https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg', {
method: 'GET',
headers: {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
});
const data = await response.json();
console.log(data);import requests
headers = {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
response = requests.get('https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg', headers=headers)
data = response.json()
print(data)const https = require('https');
const url = require('url');
const options = {
method: 'GET',
headers: {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
};
const req = https.request('https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg', options, (res) => {
let data = '';
res.on('data', (chunk) => data += chunk);
res.on('end', () => console.log(JSON.parse(data)));
});
req.end();<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'X-API-Key: your_api_key_here',
'Content-Type: application/json'
]);
$response = curl_exec($ch);
curl_close($ch);
$data = json_decode($response, true);
print_r($data);
?>package main
import (
"fmt"
"io"
"net/http"
)
func main() {
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg", nil)
req.Header.Set("X-API-Key", "your_api_key_here")
req.Header.Set("Content-Type", "application/json")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))
}require 'net/http'
require 'json'
uri = URI('https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
request = Net::HTTP::Get.new(uri)
request['X-API-Key'] = 'your_api_key_here'
request['Content-Type'] = 'application/json'
response = http.request(request)
puts JSON.pretty_generate(JSON.parse(response.body))using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Program
{
static async Task Main(string[] args)
{
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key_here");
var response = await client.GetAsync("https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg");
response.EnsureSuccessStatusCode();
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}Authentication
The Unit Converter API requires authentication via API key. Include your API key in the request header:
X-API-Key: your_api_key_hereInteractive API Playground
Test the Unit Converter API directly in your browser with live requests and responses.
Parameters
The following parameters are available for the Unit Converter API:
Convert Units
| Parameter | Type | Required | Description | Default | Example |
|---|---|---|---|---|---|
value | number | required | The value to convert | - | |
from | string | required | The unit to convert from | - | |
to | string | required | The unit to convert to | - |
Response
The Unit Converter API returns responses in JSON, XML, YAML, and CSV formats:
Example Responses
{
"status": "ok",
"error": null,
"data": {
"result": {
"result": 45.36,
"from": "100 lb",
"to": "kg"
},
"unitDefinitions": {
"from": {
"abbr": "lb",
"measure": "mass",
"system": "imperial",
"singular": "Pound",
"plural": "Pounds"
},
"to": {
"abbr": "kg",
"measure": "mass",
"system": "metric",
"singular": "Kilogram",
"plural": "Kilograms"
}
}
}
}<?xml version="1.0" encoding="UTF-8"?>
<response>
<status>ok</status>
<error xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
<data>
<result>
<result>45.36</result>
<from>100 lb</from>
<to>kg</to>
</result>
<unitDefinitions>
<from>
<abbr>lb</abbr>
<measure>mass</measure>
<system>imperial</system>
<singular>Pound</singular>
<plural>Pounds</plural>
</from>
<to>
<abbr>kg</abbr>
<measure>mass</measure>
<system>metric</system>
<singular>Kilogram</singular>
<plural>Kilograms</plural>
</to>
</unitDefinitions>
</data>
</response>
status: ok
error: null
data:
result:
result: 45.36
from: 100 lb
to: kg
unitDefinitions:
from:
abbr: lb
measure: mass
system: imperial
singular: Pound
plural: Pounds
to:
abbr: kg
measure: mass
system: metric
singular: Kilogram
plural: Kilograms
| key | value |
|---|---|
| result | {result:45.36,from:100 lb,to:kg} |
| unitDefinitions | {from:{abbr:lb,measure:mass,system:imperial,singular:Pound,plural:Pounds},to:{abbr:kg,measure:mass,system:metric,singular:Kilogram,plural:Kilograms}} |
Response Structure
All API responses follow a consistent structure with the following fields:
| Field | Type | Description | Example |
|---|---|---|---|
status | string | Indicates whether the request was successful ("ok") or failed ("error") | ok |
error | string | null | Contains error message if status is "error", otherwise null | null |
data | object | null | Contains the API response data if successful, otherwise null | {...} |
Learn more about response formats →
Response Data Fields
When the request is successful, the data object contains the following fields:
| Field | Type | Sample Value | Description |
|---|---|---|---|
result | object | - | |
â”” result | number | Converted numeric value in target units | |
â”” from | string | Original value with source unit abbreviation | |
â”” to | string | Target unit abbreviation for conversion | |
unitDefinitions | object | - | |
â”” from | object | - | |
â”” abbrPremium | string | Source unit abbreviation code | |
â”” measurePremium | string | Physical quantity being measured from | |
â”” systemPremium | string | Measurement system of source unit | |
â”” singularPremium | string | Singular name of source unit | |
â”” pluralPremium | string | Plural name of source unit | |
â”” to | object | - | |
â”” abbrPremium | string | Target unit abbreviation code | |
â”” measurePremium | string | Physical quantity being measured to | |
â”” systemPremium | string | Measurement system of target unit | |
â”” singularPremium | string | Singular name of target unit | |
â”” pluralPremium | string | Plural name of target unit |
Headers
Required and optional headers for Unit Converter API requests:
| Header Name | Required | Example Value | Description |
|---|---|---|---|
X-API-Key | required | your_api_key_here | Your APIVerve API key. Found in your dashboard under API Keys. |
Accept | optional | application/json | Specify response format: application/json (default), application/xml, or application/yaml |
User-Agent | optional | MyApp/1.0 | Identifies your application for analytics and debugging purposes |
X-Request-ID | optional | req_123456789 | Custom request identifier for tracking and debugging requests |
Cache-Control | optional | no-cache | Control caching behavior for the request and response |
GraphQL AccessALPHA
Access Unit Converter through GraphQL to combine it with other API calls in a single request. Query only the unit converter data you need with precise field selection, and orchestrate complex data fetching workflows.
Credit Cost: Each API called in your GraphQL query consumes its standard credit cost.
POST https://api.apiverve.com/v1/graphqlquery {
unitconverter(
input: {
value: 100
from: "lb"
to: "kg"
}
) {
result {
result
from
to
}
unitDefinitions {
from {
abbr
measure
system
singular
plural
}
to {
abbr
measure
system
singular
plural
}
}
}
}Note: Authentication is handled via the x-api-key header in your GraphQL request, not as a query parameter.
CORS Support
The Unit Converter API supports Cross-Origin Resource Sharing (CORS) with wildcard configuration, allowing you to call Unit Converter directly from browser-based applications without proxy servers.
| CORS Header | Value | Description |
|---|---|---|
Access-Control-Allow-Origin | * | Accepts requests from any origin |
Access-Control-Allow-Methods | * | Accepts any HTTP method |
Access-Control-Allow-Headers | * | Accepts any request headers |
Browser Usage: You can call Unit Converter directly from JavaScript running in the browser without encountering CORS errors. No proxy server or additional configuration needed.
Rate Limiting
Unit Converter API requests are subject to rate limiting based on your subscription plan. These limits ensure fair usage and maintain service quality for all Unit Converter users.
| Plan | Rate Limit | Description |
|---|---|---|
| Free | 5 requests/min | Hard rate limit enforced - exceeding will return 429 errors |
| Starter | No Limit | Production ready - standard traffic priority |
| Pro | No Limit | Production ready - preferred traffic priority |
| Mega | No Limit | Production ready - highest traffic priority |
Learn more about rate limiting →
Rate Limit Headers
When rate limits apply, each Unit Converter response includes headers to help you track your usage:
| Header | Description |
|---|---|
X-RateLimit-Limit | Maximum number of requests allowed per time window |
X-RateLimit-Remaining | Number of requests remaining in the current window |
X-RateLimit-Reset | Unix timestamp when the rate limit window resets |
Handling Rate Limits
Free Plan: When you exceed your rate limit, Unit Converter returns a 429 Too Many Requests status code. Your application should implement appropriate backoff logic to handle this gracefully.
Paid Plans: No rate limiting or throttling applied. All paid plans (Starter, Pro, Mega) are production-ready.
Best Practices for Unit Converter:
- Monitor the rate limit headers to track your Unit Converter usage (Free plan only)
- Cache unit converter responses where appropriate to reduce API calls
- Upgrade to Pro or Mega for guaranteed no-throttle Unit Converter performance
Note: Unit Converter rate limits are separate from credit consumption. You may have credits remaining but still hit rate limits when using Unit Converter on Free tier.
Error Codes
The Unit Converter API uses standard HTTP status codes to indicate success or failure:
| Code | Message | Description | Solution |
|---|---|---|---|
200 | OK | Request successful, data returned | No action needed - request was successful |
400 | Bad Request | Invalid request parameters or malformed request | Check required parameters and ensure values match expected formats |
401 | Unauthorized | Missing or invalid API key | Include x-api-key header with valid API key from dashboard |
403 | Forbidden | API key lacks permission or insufficient credits | Check credit balance in dashboard or upgrade plan |
429 | Too Many Requests | Rate limit exceeded (Free: 5 req/min) | Implement request throttling or upgrade to paid plan |
500 | Internal Server Error | Server error occurred | Retry request after a few seconds, contact support if persists |
503 | Service Unavailable | API temporarily unavailable | Wait and retry, check status page for maintenance updates |
Learn more about error handling →
Need help? Contact support with your X-Request-ID for assistance.
Integrate Unit Converter with SDKs
Get started quickly with official Unit Converter SDKs for your preferred language. Each library handles authentication, request formatting, and error handling automatically.
Available for Node.js, Python, C#/.NET, and Android/Java. All SDKs are open source and regularly updated.
Integrate Unit Converter with No-Code API Tools
Connect the Unit Converter API to your favorite automation platform without writing code. Build workflows that leverage unit converter data across thousands of apps.





All platforms use your same API key to access Unit Converter. Visit our integrations hub for step-by-step setup guides.
Frequently Asked Questions
How do I get an API key for Unit Converter?
How many credits does Unit Converter cost?
Each successful Unit Converter API call consumes credits based on plan tier. Check the pricing section above for the exact credit cost. Failed requests and errors don't consume credits, so you only pay for successful unit converter lookups.
Can I use Unit Converter in production?
The free plan is for testing and development only. For production use of Unit Converter, upgrade to a paid plan (Starter, Pro, or Mega) which includes commercial use rights, no attribution requirements, and guaranteed uptime SLAs. All paid plans are production-ready.
Can I use Unit Converter from a browser?
What happens if I exceed my Unit Converter credit limit?
When you reach your monthly credit limit, Unit Converter API requests will return an error until you upgrade your plan or wait for the next billing cycle. You'll receive notifications at 80% and 95% usage to give you time to upgrade if needed.



