Mortgage Calculator

How to use the mortgage calculator

1. Fill in the fields — they start with a worked example.
2. Read the answer, and the arithmetic shown beneath it.
3. Copy the results, or adjust the inputs to compare scenarios.

About this tool

The payment covers principal and interest; property tax and insurance are added separately because lenders usually collect them alongside, and leaving them out is what makes an affordable-looking quote unaffordable in practice.

The figure worth studying is the total interest. Over 30 years at typical rates it frequently approaches or exceeds the amount borrowed — which is the real argument for a shorter term or overpayments, both of which cut interest far more than they raise the monthly cost.

Common uses

• Estimating the monthly cost of a house at a given price.
• Comparing a 25-year term against 30.
• Seeing how much a larger deposit saves overall.

Frequently asked questions

Why is my lender's figure different?

Arrangement fees, insurance products, a different compounding convention or a rate that varies. This is the standard amortisation calculation on the numbers you enter.

Does a shorter term really save that much?

Yes. Interest accrues on a balance that falls faster, so a 25-year term typically costs noticeably less in total than 30, despite the higher monthly payment.