Mortgage Calculator

Estimate monthly mortgage payments, housing costs, total interest, and payoff totals. Add taxes, insurance, PMI, HOA, and extra payments.

How to Use

  1. Enter the home price, down payment, loan term, and interest rate.
  2. Optionally include property tax, homeowners insurance, PMI, and HOA.
  3. Add an extra monthly payment to see how faster payoff may affect total interest.
  4. Review the payment breakdown, loan summary, and Show Work section below.
Mortgage Snapshot
Payment Overview
Live summary of principal, interest, and estimated housing cost.
Monthly P&I
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Estimated Total Monthly
—
Total Interest
—
Total of Payments
—
LTV: —
Estimated Payoff: —

Payment Breakdown

Principal & Interest—
Property Tax—
Insurance—
PMI—
HOA—
Extra Payment—
Loan Inputs
Enter your mortgage details. Calculations happen in the browser using deterministic formulas.
Full purchase price of the home.
Enter dollar amount or percent. JS can keep both in sync.
Standard fixed mortgage term length.
Annual interest rate, not APR.
Optional. Used for estimated monthly payment.
Optional homeowners insurance estimate.
Optional private mortgage insurance amount.
Optional homeowners association dues.
Optional extra payment applied toward principal.
Optional. Used for payoff date display and schedule context.
Interest Rate Quick Adjust
6.75%
Extra Payment Quick Adjust
$0
Show Work (step-by-step)
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Work should be shown using standard fixed-rate mortgage formulas and monthly values where applicable.

Mortgage Formulas

Quick answer: A standard fixed-rate mortgage payment is based on loan amount, monthly interest rate, and total number of payments.

  • Loan Amount: Home Price − Down Payment
  • Monthly Rate: Annual Interest Rate ÷ 12
  • Number of Payments: Loan Term in Years × 12
  • Monthly P&I: M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]
  • Total Paid: Monthly Payment × Number of Payments
  • Total Interest: Total Paid − Loan Amount
Where P = principal, r = monthly interest rate, and n = number of monthly payments.

Loan Summary

Home Price —
Down Payment —
Loan Amount —
Interest Rate —
Loan Term —
Total Interest —
Total of Payments —
Estimated Payoff Date —

FAQ

What does principal and interest mean?

Principal is the amount borrowed. Interest is the cost of borrowing that money over time.

Why is my total monthly payment higher than the mortgage payment?

Many homeowners pay property tax, insurance, PMI, and HOA dues in addition to principal and interest.

Does making extra payments reduce interest?

In a standard fixed-rate loan, extra principal payments can reduce total interest and may shorten payoff time.

Is this calculator for fixed-rate loans?

Yes. This page is structured for standard fixed-rate mortgage calculations. Adjustable-rate loan logic can be added separately if needed.

Tool Info

Last updated:

Updates may include formula handling, amortization improvements, and UI refinements for payment breakdown and payoff estimates.