Mortgage Payment Calculator

What the mortgage payment calculator does

The mortgage payment calculator works out the monthly repayment on a home loan, along with the total interest and the total cost over the life of the loan: what you will pay each month, and what the loan will cost in the end.

A comfortable monthly payment can hide a large total cost if the term is long or the rate is high, so the calculator shows the monthly and lifetime numbers side by side.

The three results

• The monthly repayment is the fixed amount you pay each period, the figure to budget for.
• The total interest is everything the loan costs on top of what you borrowed.
• The total cost is the sum of all payments over the full term.

The monthly figure tells you whether you can manage the loan month to month; the totals tell you what you hand over in the end.

How the calculation works

1. Subtract your deposit from the home price to find the loan amount.
2. Convert the annual interest rate to a monthly rate.
3. Count the number of monthly payments across the term.
4. Apply the amortization formula so each equal payment covers the interest due plus part of the principal.

Multiplying the payment by the number of months gives the total cost, and subtracting the loan amount gives the total interest.

The inputs

• The home price and deposit, which set the loan amount.
• The interest rate, usually annual.
• The loan term in years.

How amortization shapes your payments

The payment stays the same each period, but early on most of it covers interest, with only a small part reducing the principal. As the balance falls, the interest portion shrinks and more of each payment reduces the loan.

That is why extra payments early in a loan are so effective, and why total interest can be large on a long loan. Over a long term, interest can make up a substantial share of what you repay, and even small amounts paid above the required repayment can reduce it noticeably. Two loans with the same payment can also cost very different amounts overall if their rates or terms differ.

Comparing scenarios

• A shorter term raises the monthly payment but usually cuts total interest sharply.
• A small rate change moves both the payment and the lifetime cost.
• A larger deposit lowers the loan, the payment and the total interest.
• Check that the payment leaves room for other costs and unexpected expenses.

Choosing a loan means balancing a comfortable monthly payment against a low total cost: a longer term lowers the payment but raises the total interest, and a shorter term does the opposite. You might accept a higher payment to save substantially on interest, or choose a lower payment for breathing room, knowing the lifetime cost it carries.

Beyond the calculation

The calculator covers principal and interest. Owning a home also brings insurance, maintenance, and in many places property taxes or fees, so build a buffer for them.

Rates and terms vary between lenders and change over time. Use the result to compare scenarios, then confirm the exact numbers with a lender before you commit.

This article is general information only and not financial advice.

About This Mortgage Payment Calculator

Use this mortgage payment calculator to get an instant, accurate estimate. The figures follow official guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.