Borrowing

Mortgage Payment Calculator

Calculate principal and interest payments, total interest, and the full cost of a home loan.

● Runs locally in your browserReviewed June 21, 2026

Enter your assumptions

Currency changes the display symbol only; formulas are currency-neutral.
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What this calculator helps you do

Estimate the recurring cost of a fixed-rate home loan and separate principal-and-interest from optional property tax and insurance. The calculation runs entirely in your browser; SENNA Finance does not receive the values entered into this tool.

Worked example

Example assumptions

Using the default example—home loan amount of $300,000, annual interest rate of 6.5%, loan term of 30 years, annual property tax of $3,600, monthly insurance of $120—the calculator returns estimated monthly housing cost of $2,316.20; principal and interest: $1,896.20; monthly property tax: $300.00. Change the assumptions to match your own case rather than relying on the example.

Formula and calculation basis

M = P × r(1+r)^n ÷ ((1+r)^n − 1)

Inputs are converted to the periodic units required by the formula. Results are calculated with full JavaScript numeric precision and rounded only for display.

How to interpret the result

Use the total housing cost for budgeting, but compare the principal-and-interest figure when evaluating loan offers. A lower payment can still produce a higher lifetime cost when the term is longer.

Common mistakes to avoid

  • Entering the purchase price instead of the amount borrowed after the down payment.
  • Comparing rates without adding taxes, insurance, association fees, or mortgage insurance.
  • Assuming the estimate is a lender quote or approval.

Limits and assumptions

The model assumes a fixed nominal annual rate with monthly payments. It does not automatically include closing costs, mortgage insurance, association fees, variable-rate resets, or jurisdiction-specific taxes.

Outputs are estimates, not contractual quotations, regulated disclosures, tax advice, investment advice, or a substitute for professional review.

Frequently asked questions

Does this include property tax and insurance?

Yes, when you enter them. They are added to the principal-and-interest payment to provide a broader monthly housing estimate.

Why is my lender quote different?

A lender may include mortgage insurance, escrow adjustments, fees, points, daily interest, or product-specific rounding that are not entered here.

Can I compare a 15-year and 30-year mortgage?

Yes. Calculate each term and save both scenarios to compare payment and total interest.

Sources and reference context

Independent educational referencesCFPB: How mortgage lenders calculate monthly payments ↗Consumer Financial Protection Bureau — loan and mortgage education ↗SENNA Finance calculation methodology

External references provide educational context and do not imply endorsement of SENNA Finance.

Review record

Prepared and technically reviewed by Subash Gupta

Formula engine v1.1.0. Last reviewed June 21, 2026. The reviewer is a financial-systems and technology practitioner, not a licensed financial adviser. Report suspected errors through the correction channel.