Calculate Mortgage Payments Instantly

Mortgage Calculator API.

Calculate complete mortgage payment breakdowns including monthly payment, total interest, property tax, insurance, and HOA fees. Get full amortization schedules showing principal vs interest for each payment over the life of the loan.

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Free tier, no card< 200ms responses99.9% uptime SLA

GET/v1/mortgagecalculatorlive

query

Response200 OK · sample

{
  "status": "ok",
  "error": null,
  "data": {
    "amount": 570000,
    "downpayment": 0,
    "rate": 6.8,
    "years": 30,
    "total_interest_paid": 767750.49,
    "total_loan_payment": 1337750.49,
    "interestRatio": 57.39,
    "monthly_payment": {
      "total": 3715.97,
      "mortgage": 3715.97,
      "property_tax": 0,
      "hoa": 0,
      "home_insurance": 0
    },
    "annual_payment": {
      "total": 44591.68,
      "mortgage": 44591.68,
      "property_tax": 0,
      "hoa": 0,
      "home_insurance": 0
    },
    "formatted": {
      "amount": "$570,000",
      "monthlyPayment": "$3,715.97",
      "totalInterestPaid": "$767,750.49",
      "totalLoanPayment": "$1,337,750.49"
    },
    "amortization_schedule": [
      {
        "month": 1,
        "interest_payment": 3230,
        "principal_payment": 485.97,
        "remaining_balance": 569514.03
      },
      {
        "month": 2,
        "interest_payment": 3227.25,
        "principal_payment": 488.73,
        "remaining_balance": 569025.3
      },
      {
        "month": 3,
        "interest_payment": 3224.48,
        "principal_payment": 491.5,
        "remaining_balance": 568533.8
      }
    ]
  }
}

Sample response · verify to run one live call, no signup

How it works

Mortgage Calculator API

Complete payment breakdown with taxes & fees
Full amortization schedule included
Interest ratio and total cost analysis
Pre-formatted currency values for display

1
Send one request
A single authenticated GET with the location you care about — no SDK required.
```
GET /v1/mortgagecalculator?query=…
x-api-key: your_key
```
2
We do the aggregation
Each request pulls from multiple upstream sources and computes the derived fields for you.
3
Get clean JSON back
One structured object, typically under 200 ms — ready to render.
```
{ amount, downpayment, rate, … }
```

The response

Everything in a single call.

/v1/mortgagecalculatorapplication/json

amount570000

downpayment0

rate6.8

years30

total_interest_paid767750.49

total_loan_payment1337750.49

interestRatio57.39

monthly_paymenttotal, mortgage, property_tax, hoa, home_insurance

annual_paymenttotal, mortgage, property_tax, hoa, home_insurance

formattedamount, monthlyPayment, totalInterestPaid, totalLoanPayment

amortization_schedulearray of 3

Use cases

What developers build with it.

Real applications shipping on this endpoint today — each with the numbers that made it worth wiring up.

See every use case

Real Estate Listing Platforms

Embed our Mortgage Calculator API into property listings. Let buyers input their down payment and see personalized payment estimates including estimated taxes and insurance.

Personalized payment estimatesInclude taxes, insurance, HOADynamic down payment scenarios

Higherengagement

More leadsfrom qualified buyers

Better UXfor shoppers

Mortgage Comparison Tool

Use our API to calculate multiple scenarios in parallel. Show side-by-side comparisons of monthly payments, total interest, and total cost for different terms and rates.

Easy scenario comparisonTotal cost visibilityInterest savings calculation

Smarterdecisions

Clearcost comparison

Save usersthousands

Amortization Schedule Generator

Our API returns a complete amortization schedule showing each month's principal payment, interest payment, and remaining balance. Perfect for visualizing the payoff journey.

Full month-by-month breakdownPrincipal vs interest splitRemaining balance tracking

Financialliteracy

Clearpayoff path

Usertrust

Start coding

Call it in your language.

Copy a working request, or install a typed SDK. Same endpoint, same key.

const res = await fetch("https://api.apiverve.com/v1/mortgagecalculator", { method: "POST", headers: { "x-api-key": "YOUR_API_KEY" } });
const { data } = await res.json();
console.log(data);

Included in your key

One subscription, the whole calculate mortgage payments instantly stack.

Every related API ships with your key — no separate plans, no extra keys, one bill.

See pricing

8APIs in this bundle

99.9%uptime SLA

The bundle

mortgagecalculatorYou’re hereloancalculator numbertowords currencyconverter salestax zipcodes mathcalculator tipcalculator

No code required

Wire it into the tools you already run.

Ready-made recipes for Zapier, Make, and n8n — trigger on an event, and the data lands where your team works.

Google Sheets

Mortgage Estimates in Google Sheets

WhenNew row added in Google Sheets

ThenCalculate mortgage for amount, rate, and years in row → write monthly_payment.total and total_interest_paid back to the row

Slack

Mortgage Quote Bot in Slack

WhenSlack slash command or message

ThenCalculate mortgage for provided amount, rate, years → post formatted.monthlyPayment and formatted.totalInterestPaid to Slack

Airtable

Mortgage Payment Calculator in Airtable

WhenNew record created in Airtable

ThenCalculate mortgage for amount, rate, years fields → update record with monthly_payment.total, total_interest_paid, and formatted.monthlyPayment

Notion

Property Evaluation Database in Notion

WhenNew page created in Notion database

ThenCalculate mortgage for property details → update page with monthly_payment.total, total_interest_paid, and interestRatio

Salesforce

Mortgage Estimate on Salesforce Opportunities

WhenNew opportunity created in Salesforce

ThenCalculate mortgage for opportunity loan amount and rate → update with monthly_payment.total and total_interest_paid

GitHub

Mortgage API Test Cases in GitHub

WhenNew issue created in GitHub

ThenCalculate mortgage for test parameters → add monthly_payment, total_interest_paid, and interestRatio as issue comment

Browse all integrations

Learn

Understand the data behind the API.

Understanding Mortgage Calculations

How mortgage payments, interest, and amortization work.

Questions about the API

What inputs are required for mortgage calculations?

Required: loan amount, interest rate, and loan term in years. Optional: down payment, annual property tax, annual home insurance, and annual HOA fees. All optional fields default to 0 if not provided.

How is the monthly payment calculated?

The monthly mortgage payment (principal + interest) is calculated using the standard amortization formula. Property tax, insurance, and HOA are then divided by 12 and added to get the total monthly payment.

What does the amortization schedule include?

The amortization schedule shows each month's payment broken down into principal payment, interest payment, and remaining balance. This helps visualize how payments shift from mostly interest to mostly principal over time.

Can I compare different loan scenarios?

Yes! Make multiple API calls with different parameters (loan terms, rates, down payments) to compare scenarios. The response includes total interest paid and total loan cost for easy comparison.

Are property taxes and insurance included?

Yes, if you provide annual_propertytax, annual_homeinsurance, and annual_hoa values, they're included in both monthly and annual payment totals. These are optional parameters.

What loan terms are supported?

Loan terms from 1 to 50 years are supported. Common terms are 15 and 30 years. The amortization schedule adjusts to show the full loan duration.

How is the interest ratio calculated?

The interest ratio represents the percentage of your total payments that go toward interest versus principal. A 45% ratio means 45% of total payments are interest.

Does this work for refinancing calculations?

Yes! Use your current loan balance as the amount and compare different rate/term combinations. The total interest saved can help decide if refinancing makes sense.