Calculate a full mortgage payment: principal, interest, taxes and insurance

A mortgage payment is more than principal and interest. Buyers compare the full monthly cost, which also includes property tax, home insurance, HOA fees and, below 20% down, private mortgage insurance.

The Mortgage Calculator returns that full PITI figure and its parts in one call, so a listing page, budgeting app or AI assistant can show the number people actually pay.

Make the request

Send your API key in the x-api-key header. Free accounts include 1,000 calls a month.

curl -X POST https://apistack.online/api/finance/mortgage-calculator/v1 \
  -H "x-api-key: $APISTACK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"calculation":"payment","homePrice":450000,"downPaymentPercent":20,"annualRate":6.25,"termYears":30,"propertyTax":5400,"homeInsurance":1500,"hoaFees":0,"includePMI":true,"includeBreakdown":true}'
200 OK · response
{
  "success": true,
  "data": {
    "mortgageDetails": {
      "homePrice": 450000,
      "downPayment": 90000,
      "downPaymentPercent": 20,
      "loanAmount": 360000,
      "annualRate": 6.25,
      "termYears": 30,
      "mortgageType": "conventional",
      "includePMI": false
    },
    "paymentCalculation": {
      "principalAndInterest": 2216.58,
      "pmi": 0,
      "propertyTax": 450,
      "homeInsurance": 125,
      "hoaFees": 0,
      "totalMonthlyPayment": 2791.58
    },
    "paymentBreakdown": {
      "firstYearInterest": 22380.520000000004,
      "totalInterest": 437969.49,
      "totalPayments": 360
    }
  }
}

Response abridged: some fields (timestamps, metadata) omitted.

Read the result

propertyTax and homeInsurance are annual amounts in the request and monthly amounts in the response. With 20% down there is no PMI; drop downPaymentPercent below 20 and the pmi line appears.

Just the loan?

For a plain loan payment without taxes and insurance (car, personal or business loans), use the Loan Calculator API.

Give it to your AI agent

The same API is available as an MCP tool. Add APIStack to Claude, Cursor, VS Code or any MCP client:

{
  "mcpServers": {
    "apistack": {
      "url": "https://apistack.online/api/mcp/connect",
      "headers": { "x-api-key": "YOUR_API_KEY" }
    }
  }
}

Then ask: “What is the full monthly payment on a $450,000 home with 20% down at 6.25% for 30 years, with $5,400 property tax and $1,500 insurance a year?” See MCP setup for every client.

API reference and live testGet a free API key

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