Density Calculator

science 1 credits / call v2026-04-22

Solve density, mass, or volume with common unit conversions.

Use this endpoint when your app or AI agent needs exact JSON instead of spending LLM tokens on well-defined utility work.

Prefer the browser version? Open the Density Calculator on miniwebtool.com.

Start free — get a key → 1,000 credits · no card · 30 seconds

Endpoint

POST https://api.miniwebtool.com/v1/tools/density-calculator/run

Request body

Field Type Req.
solve_for
density | mass | volume
str
mass float | None
volume float | None
density float | None
mass_unit
mg | g | kg | tonne | oz | lb
str
volume_unit
mm3 | cm3 | dm3 | m3 | mL | L | in3 | ft3 | gal_us | gal_uk
str
density_unit
g/cm3 | kg/m3 | kg/L | lb/ft3 | lb/in3 | lb/gal
str

Cost & access

  • 1 credit per successful call.
  • Starts on: Free.
  • Max payload: 65536 bytes.
  • Privacy mode: hash_only
  • Available on: free, starter, pro, business, scale

Response envelope

{
  "request_id": "01K...",
  "tool": "density-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 1,
  "result": { ... }
}

Try it

Stored only in this browser tab. Don't have one? Start free — get a key →
density | mass | volume
mg | g | kg | tonne | oz | lb
mm3 | cm3 | dm3 | m3 | mL | L | in3 | ft3 | gal_us | gal_uk
g/cm3 | kg/m3 | kg/L | lb/ft3 | lb/in3 | lb/gal

Code examples

curl -X POST https://api.miniwebtool.com/v1/tools/density-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{}'
import requests

resp = requests.post(
    'https://api.miniwebtool.com/v1/tools/density-calculator/run',
    headers={'Authorization': 'Bearer mwt_live_YOUR_KEY'},
    json={},
)
resp.raise_for_status()
print(resp.json())
const resp = await fetch(
  'https://api.miniwebtool.com/v1/tools/density-calculator/run',
  {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer mwt_live_YOUR_KEY',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({}),
  }
);
const data = await resp.json();
console.log(data);
<?php
$ch = curl_init('https://api.miniwebtool.com/v1/tools/density-calculator/run');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer mwt_live_YOUR_KEY',
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([

]),
]);
$resp = curl_exec($ch);
curl_close($ch);
print_r(json_decode($resp, true));
require 'net/http'
require 'json'
require 'uri'

uri = URI('https://api.miniwebtool.com/v1/tools/density-calculator/run')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = (uri.scheme == 'https')

req = Net::HTTP::Post.new(uri)
req['Authorization'] = 'Bearer mwt_live_YOUR_KEY'
req['Content-Type'] = 'application/json'
req.body = {

}.to_json

resp = http.request(req)
puts JSON.parse(resp.body).inspect
package main

import (
  "bytes"
  "encoding/json"
  "fmt"
  "io"
  "net/http"
)

func main() {
  body, _ := json.Marshal(map[string]interface{}{
,
  })
  req, _ := http.NewRequest("POST", "https://api.miniwebtool.com/v1/tools/density-calculator/run", bytes.NewReader(body))
  req.Header.Set("Authorization", "Bearer mwt_live_YOUR_KEY")
  req.Header.Set("Content-Type", "application/json")

  resp, err := http.DefaultClient.Do(req)
  if err != nil { panic(err) }
  defer resp.Body.Close()
  out, _ := io.ReadAll(resp.Body)
  fmt.Println(string(out))
}
import java.net.URI;
import java.net.http.*;

var client = HttpClient.newHttpClient();
var req = HttpRequest.newBuilder()
    .uri(URI.create("https://api.miniwebtool.com/v1/tools/density-calculator/run"))
    .header("Authorization", "Bearer mwt_live_YOUR_KEY")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString("{}"))
    .build();

var resp = client.send(req, HttpResponse.BodyHandlers.ofString());
System.out.println(resp.body());

How to call Density Calculator

  1. 1 Get an API key
    Get an API key. Sign up free for a bearer token. 1,000 credits/month, no card.
  2. 2 Assemble the JSON body
    Required fields: . See the Request body table below for the full schema.
  3. 3 POST to https://api.miniwebtool.com/v1/tools/density-calculator/run
    Headers: Authorization: Bearer <key> and Content-Type: application/json. Copy-paste snippets in 7 languages are under Code examples.
  4. 4 Parse the response
    Envelope: {request_id, tool, tool_version, credits_used, result}. The typed output lives in result.

Frequently asked

What does the Density Calculator API do?

Solve density, mass, or volume with common unit conversions. Use it when you need exact JSON instead of asking an LLM to recreate well-defined utility logic.

How much does one call to Density Calculator cost?

1 credit per successful call. Failed calls (validation errors, 5xx) don't bill.

What parameters does the Density Calculator API require?

Required fields: (none). Full schema at /v1/openapi.json.

Is the Density Calculator API deterministic?

Yes — same input, same output, forever. Tool version 2026-04-22; output shape is stable within a major version.

Can an AI agent call the Density Calculator API?

Yes. Connect to https://api.miniwebtool.com/v1/mcp over the Model Context Protocol. The agent discovers `density-calculator` with its JSON Schema automatically, so the model can plan while MiniWebtool handles the exact tool result.

What format does the API return?

JSON with a stable envelope: `{request_id, tool, tool_version, credits_used, result}`. Errors are RFC 7807 `application/problem+json`.

Use from an AI agent

Every endpoint on this site is also exposed via the Model Context Protocol at https://api.miniwebtool.com/v1/mcp. Claude, Cursor, and any MCP-capable agent can discover this tool (density-calculator) and its JSON Schema automatically — no client codegen.

# List tools the agent can call
curl -s https://api.miniwebtool.com/v1/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' \
 | jq '.result.tools[] | select(.name=="density-calculator")'