Mortgage Calculator

A mortgage calculator helps you understand the true cost of buying a home before you ever sign a contract. By entering the home price, your down payment, the interest rate offered by your lender and the length of the loan, you instantly see the monthly payment you will be committing to for years to come.

Buying a property is the largest financial decision most people ever make. Small differences in interest rate or term can change your total cost by tens of thousands. This calculator removes the guesswork so you can compare offers and budget with confidence.

The calculator first subtracts your down payment from the home price to determine the loan principal — the amount you actually borrow.

It then applies the monthly interest rate (your annual rate divided by twelve) across the number of monthly payments in your term to produce a fixed, fully-amortizing monthly payment covering both principal and interest.

Finally it builds a month-by-month amortization schedule showing how each payment is split between interest and principal, and how your remaining balance shrinks over time.

M = P × r × (1 + r)^n / ((1 + r)^n − 1)

M is the monthly payment, P is the loan principal, r is the monthly interest rate (annual rate ÷ 12 ÷ 100), and n is the total number of monthly payments (years × 12).

Early in the loan most of your payment goes to interest; over time the balance shifts toward principal, which is why total interest can be a large share of the overall cost.

• On a $350,000 home with $70,000 down at 6.5% over 30 years, you borrow $280,000 and pay roughly $1,770 per month, with total interest well over $350,000 across the life of the loan.
• Shortening the term to 15 years raises the monthly payment but dramatically cuts the total interest, often saving six figures.

• Know your real monthly commitment before house-hunting.
• Compare lenders, rates and terms side by side.
• See exactly how much interest you pay over the life of the loan.
• Understand how extra down payment reduces both payment and interest.

To get reliable results from the Mortgage Calculator, take a moment to gather accurate, up-to-date figures before you start. Small differences in the inputs you enter — an interest rate, a time horizon, or a contribution amount — can lead to meaningfully different outcomes, so it pays to be precise.

Treat the calculator as a planning aid rather than a crystal ball. Run several scenarios — an optimistic case, a conservative case, and something in between — so you understand the range of possibilities instead of fixating on a single number. Revisit your numbers periodically as your circumstances, rates, and goals change.

• Double-check that rates are entered as annual figures unless stated otherwise.
• Compare best-case and worst-case scenarios, not just the average.
• Account for fees, taxes and inflation where they apply to your situation.
• Re-run the numbers whenever your income, rates or goals change.

The most common error people make with any real estate calculator is entering inconsistent units — for example mixing monthly and annual figures, or confusing a nominal rate with an effective one. Read each field label carefully so your inputs line up.

Another frequent pitfall is treating a single estimate as a guarantee. Real-world results are shaped by factors a calculator cannot fully capture, including changing rates, fees, taxes and your own eligibility. Use the output as a well-informed estimate and confirm important decisions with a qualified professional.

The Mortgage Calculator turns a handful of inputs into a clear, actionable result so you can plan with confidence. By understanding the formula behind it, experimenting with different scenarios, and avoiding the common mistakes above, you can use this real estate tool to make smarter, better-informed money decisions.

Remember that every result is an estimate for educational purposes. Pair what you learn here with the related calculators and guides on this page to build a fuller picture of your finances.