Your monthly mortgage payment

With a repayment mortgage — the most common type in the UK — each monthly payment covers two things: interest charged by your lender and a portion of the original loan (capital). In the early years, the bulk of your payment goes towards interest — which is why the total interest figure can look shockingly high. As you gradually pay down the balance, more of each payment goes to capital and less to interest. This process is called amortisation.

How the term length affects your payments

Choosing a longer term (say 30 or even 35 years instead of 25) reduces your monthly payment but increases the total interest you'll pay — often by tens of thousands of pounds. For example, a £220,000 mortgage at 4.5% costs around £1,222 per month over 25 years, but just £1,111 per month over 30 years. That £111 monthly saving comes at a cost: roughly £20,000 more in total interest over the life of the loan. Conversely, a shorter term means higher monthly payments but significantly less interest overall. Use the term slider above to see this trade-off in real time.

Repayment vs interest-only mortgages

An interest-only mortgage means your monthly payments only cover the interest — the balance itself never goes down. At the end of the term, you still owe the full original loan amount. These are much less common for residential mortgages in the UK today, but some buy-to-let investors still use them. We show the interest-only figure above for comparison so you can see the difference. With a repayment mortgage, you're guaranteed to own your home outright by the end of the term, provided you keep up with payments.

What happens when your fixed rate ends

Most UK borrowers choose a fixed-rate deal lasting two to five years. When that deal ends, your lender will move you onto their Standard Variable Rate (SVR), which is almost always significantly higher — often 2–3 percentage points above your fixed rate. This can add hundreds of pounds to your monthly payment overnight. The smart move is to start shopping for a new deal a few months before your fixed rate expires. Remortgaging to a competitive new rate can save you thousands each year and is one of the simplest ways to manage your mortgage costs.

Reduce your term, not just your rate

Want to pay less interest without increasing your required monthly payment? Regular overpayments can knock years off your mortgage without any formal change to your deal. Most UK fixed-rate mortgages allow overpayments of up to 10% of the outstanding balance per year without penalty. Try our Overpayment Calculator to find your Freedom Date and see exactly how much you'd save. If you're still at the planning stage, check what you can afford to borrow in the first place, or factor in stamp duty costs to get the full picture.