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Mortgage Calculator API

Free, open JSON API for mortgage calculations. All endpoints accept standard HTTP GET requests with query parameters — no API key, no sign-up, no rate limits. CORS is enabled for all origins so you can call the API directly from the browser.

No authentication required CORS enabled JSON responses For informational use — not financial advice

Quick start

# Get a mortgage payment summary
GET http://calculatemymortgage.org/calculators/api/calculate.php?principal=280000&rate=6.5&term=30

# Example response
{
  "principal": 280000,
  "rate": 6.5,
  "term_years": 30,
  "monthly_payment": 1769.49,
  "monthly_pi": 1769.49,
  "total_interest": 357014.76,
  "schedule_url": "http://calculatemymortgage.org/calculators/api/amortization.php?..."
}