Unit Converter

Overview

A unit conversion API that replaces hand-maintained conversion tables in your code. It covers 185 units across 23 measures, so the everyday conversions are one call each: liters to gallons, miles per hour to kilometers per hour, Celsius to Fahrenheit, megabytes to gigabytes, psi to bar, pounds to kilograms, and kilowatt-hours to joules. Beyond length, area, mass, volume and temperature it handles time, speed, pace, pressure, digital storage, parts per million, frequency, angles, illuminance, volume flow rate and electrical units from volts and amperes to watts and kilowatt-hours. Results are rounded to 2 decimal places. On paid plans, precision returns up to 10 decimal places, so very small results no longer round to zero, and conversions=true returns the same value in every unit of its measure in one call, such as a mass in micrograms through metric tons.

Live Test Unit Converter API →

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.

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curl "https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg&precision=4&conversions=true" \
  -H "x-api-key: your_api_key_here"

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const res = await fetch('https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg&precision=4&conversions=true', {
  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);

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import requests

res = requests.get(
    "https://api.apiverve.com/v1/unitconverter?value=100&from=lb&to=kg&precision=4&conversions=true",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

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

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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&precision=4&conversions=true", 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.

Parameters

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

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.

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{
  "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"
      }
    },
    "conversions": {
      "mcg": 45359200000,
      "mg": 45359200,
      "g": 45359.2,
      "kg": 45.36,
      "mt": 0.05,
      "oz": 1600,
      "lb": 100,
      "t": 0.05
    }
  }
}

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.

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.

Supported Units

All 185 units across 23 measures. Units convert only within the same measure (length to length, pressure to pressure). Codes are case-sensitive: Mb is megabits and MB is megabytes. Miles per hour is m/h. Temperature codes also accept lowercase (c, f, k, r).

Use cases

Measurement Converters

Convert measurements such as weight, length, area, temperature, and more by using the Unit Converter API. Use the API to convert units between different systems

Unit Standardization

Standardize units across different systems by using the Unit Converter API. Convert units to a common standard for consistency and compatibility

Unit Calculation

Perform unit calculations by using the Unit Converter API to convert units in mathematical operations. Use the API to simplify unit conversions in calculations

Other ways to use Unit Converter

Set up Unit 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.

Related

More in Data Conversion: