For the complete documentation index, see llms.txt.

Mortgage Calculator API

finance 5 credits / call v2026-04-22

Monthly payment, total interest, LTV, and optional amortization schedule.

One POST adds Mortgage Calculator to your app, site, workflow, or agent — formula, validation, edge cases, and docs already handled.

prefer a UI? Open the Mortgage Calculator on miniwebtool.com →

Start Pro → Requires Pro+ · $79/mo or get a free key to explore
Starts on Pro
Free keys can view docs and examples, but calls to this endpoint require Pro or higher.
Start Pro →

Endpoint

POST · 5cr
POST https://api.miniwebtool.com/v1/tools/mortgage-calculator/run

Request body

Field Type Req.
home_price float
down_payment float
annual_rate_percent float
years float
include_schedule bool
property_tax_annual float
home_insurance_annual float
pmi_annual_percent float

Cost & access

  • 5 credits per successful call — failed calls refund.
  • Starts on: Pro or higher.
  • Max payload: 4096 bytes.
  • Privacy mode: hash_only
  • Available on: pro, business, scale

Response envelope

{
  "request_id": "01K...",
  "tool": "mortgage-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 5,
  "result": { ... }
}

Try it

Stored only in this browser tab. Playground test key is prefilled and only works on this page. Get a live key →

Get a free key to explore

This endpoint starts on Pro ($79/mo) — Start Pro →. A free key still covers 1,000 calls/mo on free-tier endpoints.

One verification click, then your key + a ready-to-run request. No card, no spam.

Code examples

curl -X POST https://api.miniwebtool.com/v1/tools/mortgage-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"home_price":500000,"down_payment":100000,"annual_rate_percent":6.5,"years":30,"include_schedule":false,"property_tax_annual":6000,"home_insurance_annual":1800,"pmi_annual_percent":0}'
import requests

resp = requests.post(
    'https://api.miniwebtool.com/v1/tools/mortgage-calculator/run',
    headers={'Authorization': 'Bearer mwt_live_YOUR_KEY'},
    json={'home_price': 500000, 'down_payment': 100000, 'annual_rate_percent': 6.5, 'years': 30, 'include_schedule': False, 'property_tax_annual': 6000, 'home_insurance_annual': 1800, 'pmi_annual_percent': 0},
)
resp.raise_for_status()
data = resp.json()
print(data)
const resp = await fetch(
  'https://api.miniwebtool.com/v1/tools/mortgage-calculator/run',
  {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer mwt_live_YOUR_KEY',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({"home_price":500000,"down_payment":100000,"annual_rate_percent":6.5,"years":30,"include_schedule":false,"property_tax_annual":6000,"home_insurance_annual":1800,"pmi_annual_percent":0}),
  }
);
const data = await resp.json();
console.log(data);
<?php
$ch = curl_init('https://api.miniwebtool.com/v1/tools/mortgage-calculator/run');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer mwt_live_YOUR_KEY',
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([
    'home_price' => 500000,
    'down_payment' => 100000,
    'annual_rate_percent' => 6.5,
    'years' => 30,
    'include_schedule' => false,
    'property_tax_annual' => 6000,
    'home_insurance_annual' => 1800,
    'pmi_annual_percent' => 0
]),
]);
$resp = curl_exec($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/mortgage-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 = {
  'home_price' => 500000,
  'down_payment' => 100000,
  'annual_rate_percent' => 6.5,
  'years' => 30,
  'include_schedule' => false,
  'property_tax_annual' => 6000,
  'home_insurance_annual' => 1800,
  'pmi_annual_percent' => 0
}.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{}{
    "home_price": 500000,
    "down_payment": 100000,
    "annual_rate_percent": 6.5,
    "years": 30,
    "include_schedule": false,
    "property_tax_annual": 6000,
    "home_insurance_annual": 1800,
    "pmi_annual_percent": 0,
  })
  req, _ := http.NewRequest("POST", "https://api.miniwebtool.com/v1/tools/mortgage-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/mortgage-calculator/run"))
    .header("Authorization", "Bearer mwt_live_YOUR_KEY")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString("{\"home_price\":500000,\"down_payment\":100000,\"annual_rate_percent\":6.5,\"years\":30,\"include_schedule\":false,\"property_tax_annual\":6000,\"home_insurance_annual\":1800,\"pmi_annual_percent\":0}"))
    .build();

var resp = client.send(req, HttpResponse.BodyHandlers.ofString());
System.out.println(resp.body());
how-to call mortgage-calculator
  1. Get an API key
    Get an API key. Choose the Pro plan or higher to receive a bearer token with access to this endpoint.
  2. Assemble the JSON body
    Required fields: home_price, down_payment, annual_rate_percent, years, . See the Request body table above for the full schema.
  3. POST to https://api.miniwebtool.com/v1/tools/mortgage-calculator/run
    Headers: Authorization: Bearer <key> and Content-Type: application/json. Copy-paste snippets in 7 languages are under Code examples.
  4. Parse the response
    Envelope: {request_id, tool, tool_version, credits_used, result}. The typed output lives in result.
faq frequently asked
What does the Mortgage Calculator API do?+

Monthly payment, total interest, LTV, and optional amortization schedule. Use it to add this utility without rebuilding formulas, validation, examples, and documentation.

How much does one call to Mortgage Calculator cost?+

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

What parameters does the Mortgage Calculator API require?+

Required fields: home_price, down_payment, annual_rate_percent, years. Full schema at /v1/openapi.json.

Is the Mortgage 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 Mortgage Calculator API?+

Yes. Connect to https://api.miniwebtool.com/v1/mcp over the Model Context Protocol. The agent discovers `mortgage-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`.

mcp 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 (mortgage-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=="mortgage-calculator")'
see-also related finance tools