STANDS4 Web Services:

Conversions API

The Conversions API enables you to get instant and accurate answers to complex mathematical expressions and thousands of conversion related queries that can be posted in a natural language representation without any strict syntax. Please visit our conversions help page for more information.

Request URL:

Request parameters:

Parameter Value Required Default Description
uid string Y  

Your API user id

tokenid string Y  

Your valid developer token id

expression string Y  

The expressions you would like to evaluate

format string N xml

The format in which you want the result returned (xml or json)

Sample request URL:

Response elements:

Element Description

Contains all of the query responses


The error code associated with this query evaluation (0 means success)


The error message associated with this query evaluation


The formatted answer to the evaluated query


The category that this conversion query belongs to

Sample response:

<?xml version="1.0" encoding="UTF-8"?>
    <result>5 Kilograms = 14.7 Pounds</result>
	"results": {
		"errorCode": "0",
		"errorMessage": "",
		"result": "5 Kilograms = 14.7 Pounds",
		"category": "Weight"

Example use case:

RefSeek, a web search engine for students and researchers, is using the API to provide its users with instant answers to conversion related queries.

Want to use this service?

The Conversions API service is free to use for up to 100 queries per day.

For a premium commercial license, please contact us.

Apply here