Amortization Calculator API

POST https://api.findutils.com/api/tools/amortization-calculator/execute

Return a full loan amortization schedule (one row per month with payment, principal, interest, extra payment, balance) plus totals, interest saved, months saved, and the payoff month. Rate is a yearly percentage; payments are monthly.

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Request body

application/json

loan_amount

number required

Loan principal.
interest_rate

number required

Yearly interest rate in percent (6.5 = 6.5%). Must be > 0.
loan_term_years

integer required

Loan term in years (1-40).
extra_payment

number optional

Optional extra principal paid every month. Default: 0.
start_month

string optional

First payment month as YYYY-MM. Default: the current UTC month.

Example arguments

Verified

{
  "loan_amount": 250000,
  "interest_rate": 6.5,
  "loan_term_years": 30,
  "start_month": "2026-01"
}

curl -X POST https://api.findutils.com/api/tools/amortization-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "loan_amount": 250000,
    "interest_rate": 6.5,
    "loan_term_years": 30,
    "start_month": "2026-01"
  }'

const response = await fetch('https://api.findutils.com/api/tools/amortization-calculator/execute', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({"loan_amount":250000,"interest_rate":6.5,"loan_term_years":30,"start_month":"2026-01"}),
});
const data = await response.json();

import requests

response = requests.post(
    "https://api.findutils.com/api/tools/amortization-calculator/execute",
    json={"loan_amount":250000,"interest_rate":6.5,"loan_term_years":30,"start_month":"2026-01"},
)
data = response.json()

$ch = curl_init('https://api.findutils.com/api/tools/amortization-calculator/execute');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"loan_amount":250000,"interest_rate":6.5,"loan_term_years":30,"start_month":"2026-01"}',
    CURLOPT_RETURNTRANSFER => true,
]);
$data = json_decode(curl_exec($ch), true);

Also an MCP tool

Call amortization_calculator from Claude, Cursor or any MCP client. Same arguments, same output.

https://mcp.findutils.com

MCP reference

Rate limit: 60 a minute, per IP
Auth: None
REST id: amortization-calculator
MCP name: amortization_calculator
Category: Finance
Machine-readable: openapi.json · markdown.md

Request body

Example arguments

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