Mortgage Term Comparison Calculator
Compare the same mortgage over three different terms to see how the payment and the total interest change, and what a shorter term really saves.
💼 Are you a real estate agent or broker? Send this calculator to your buyers on your own branded listing page — every enquiry comes straight to your WhatsApp. Create free agent page →Term length is the decision with the largest effect on total cost, and it is usually made by default rather than deliberately. A longer term lowers the payment and raises the total interest sharply, because a large balance stays outstanding for far longer.
Seeing three terms side by side makes the trade explicit: a specific monthly figure against a specific lifetime saving, so you can decide what the flexibility is worth rather than accepting whatever the lender defaults to.
The comparison
The same amount and rate are run through the standard payment formula at three different terms. Total interest at each is the payment multiplied by the number of months, less the amount borrowed.
Worked example
Borrowing 300,000 at 6.5%: fifteen years costs 2,613 a month and 170,400 of interest; twenty-five years costs 2,026 and 307,700; thirty years costs 1,896 and 382,600. Choosing fifteen years over thirty costs 717 more each month and saves about 212,200 in interest.
A middle path that keeps the flexibility
Taking the longer term and overpaying voluntarily gives nearly the same interest saving while leaving you free to stop overpaying in a difficult month. The committed shorter term is cheaper only if you would otherwise not have made the overpayments.
Turn a calculation into an enquiry
Buyers who run these numbers are ready to talk. Give every listing its own page with your photo, phone and WhatsApp on it — leads land straight on your phone.
Create your free property pageFrequently asked questions
Is a shorter term always better?
Financially yes, but only if the higher payment is genuinely affordable in a bad month as well as a good one. A shorter term you cannot sustain is far more expensive than a longer one you can.
Can I change the term later?
Most lenders allow it, usually at a remortgage and subject to affordability. Shortening is generally straightforward; extending may be limited by your age at the end of the proposed term.
Why does a longer term cost so much more?
Because interest is charged on the outstanding balance, and a longer term keeps that balance high for many more years. The extra five years between twenty-five and thirty add far more interest than the payment reduction suggests.