Powerful RESTful API for unit conversions with 15-decimal precision. Perfect for developers building apps, websites, and integrations that need accurate measurement conversions.
Free tier includes 1000 requests per day - perfect for development and small applications
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Send HTTP requests to our conversion endpoints
Receive precise conversions in JSON format
Everything you need for professional unit conversion integration
Laboratory-grade accuracy for scientific and engineering applications
Comprehensive coverage of length, weight, temperature, volume, and specialized units
Sub-100ms response times with 99.9% uptime SLA
HTTPS encryption, CORS support, and rate limiting for security
Works with JavaScript, Python, PHP, Java, C#, Ruby, Go, and more
1000 requests per day free - perfect for development and small apps
Complete reference for all available endpoints
https://api.precisionconvert.io/v1
All API requests should be made to this base URL with the appropriate endpoint path.
Include your API key in the request header:
Authorization: Bearer YOUR_API_KEY
Convert a value from one unit to another with 15-decimal precision.
| Parameter | Type | Required | Description |
|---|---|---|---|
value |
number | Required | The numeric value to convert |
from |
string | Required | Source unit (e.g., "meters", "pounds", "celsius") |
to |
string | Required | Target unit (e.g., "feet", "kilograms", "fahrenheit") |
precision |
integer | Optional | Decimal places (1-15, default: 6) |
curl -X GET "https://api.precisionconvert.io/v1/convert?value=10&from=meters&to=feet&precision=6" \ -H "Authorization: Bearer YOUR_API_KEY"
const response = await fetch('https://api.precisionconvert.io/v1/convert?value=10&from=meters&to=feet&precision=6', {
headers: {
'Authorization': 'Bearer YOUR_API_KEY'
}
});
const data = await response.json();
console.log(data);
import requests
url = "https://api.precisionconvert.io/v1/convert"
params = {
"value": 10,
"from": "meters",
"to": "feet",
"precision": 6
}
headers = {
"Authorization": "Bearer YOUR_API_KEY"
}
response = requests.get(url, params=params, headers=headers)
data = response.json()
print(data)
$url = "https://api.precisionconvert.io/v1/convert";
$params = http_build_query([
'value' => 10,
'from' => 'meters',
'to' => 'feet',
'precision' => 6
]);
$context = stream_context_create([
'http' => [
'header' => "Authorization: Bearer YOUR_API_KEY"
]
]);
$response = file_get_contents($url . '?' . $params, false, $context);
$data = json_decode($response, true);
print_r($data);
{
"success": true,
"result": {
"value": 10,
"from": "meters",
"to": "feet",
"converted_value": 32.808399,
"precision": 6,
"conversion_factor": 3.280839895013123
},
"timestamp": "2025-01-21T12:00:00Z",
"request_id": "req_abc123"
}
Get a list of all available units organized by category.
| Parameter | Type | Required | Description |
|---|---|---|---|
category |
string | Optional | Filter by category (length, weight, temperature, volume, etc.) |
{
"success": true,
"units": {
"length": [
{"id": "meters", "name": "Meters", "symbol": "m"},
{"id": "feet", "name": "Feet", "symbol": "ft"},
{"id": "inches", "name": "Inches", "symbol": "in"}
],
"weight": [
{"id": "kilograms", "name": "Kilograms", "symbol": "kg"},
{"id": "pounds", "name": "Pounds", "symbol": "lbs"}
]
}
}
Convert multiple values in a single request for improved efficiency.
{
"conversions": [
{"value": 10, "from": "meters", "to": "feet"},
{"value": 25, "from": "celsius", "to": "fahrenheit"},
{"value": 100, "from": "kilograms", "to": "pounds"}
],
"precision": 6
}
{
"success": true,
"results": [
{"value": 10, "from": "meters", "to": "feet", "converted_value": 32.808399},
{"value": 25, "from": "celsius", "to": "fahrenheit", "converted_value": 77.0},
{"value": 100, "from": "kilograms", "to": "pounds", "converted_value": 220.462262}
],
"total_conversions": 3
}
Understanding API error responses and status codes
| Status Code | Description | Common Causes |
|---|---|---|
| 200 | Success | Request completed successfully |
| 400 | Bad Request | Invalid parameters or missing required fields |
| 401 | Unauthorized | Invalid or missing API key |
| 429 | Rate Limited | Too many requests - upgrade plan or wait |
| 500 | Server Error | Internal server error - contact support |
{
"success": false,
"error": {
"code": "INVALID_UNIT",
"message": "The unit 'invalid_unit' is not supported",
"details": "Supported units can be found at /v1/units endpoint"
},
"timestamp": "2025-01-21T12:00:00Z",
"request_id": "req_error123"
}
Flexible plans to meet your application's needs
Official libraries to get you started faster
Get help when you need it