How you repay a mortgage, whether you chip away at the loan each month or just pay the interest, makes a big difference to your payments and what you owe. This guide explains repayment versus interest-only mortgages: how each works, their pros and cons, and when each is used.
The two ways to structure a mortgage
There are two main ways to structure mortgage repayments: repayment (also called capital and interest), where each payment reduces the loan, and interest-only, where you pay just the interest and the loan stays the same. The choice affects your monthly payment, how much you owe over time, and how the loan is eventually cleared. Understanding both helps you choose the right structure for your situation.
How a repayment mortgage works
With a repayment mortgage, each monthly payment covers the interest plus a portion of the capital, so the balance gradually falls and the mortgage is fully repaid by the end of the term. Early on, more of the payment is interest, with more going to capital over time. By the end, you owe nothing and own the home outright. Most residential mortgages are repayment for this reason.
How an interest-only mortgage works
With an interest-only mortgage, your monthly payment covers only the interest, so the loan balance stays the same throughout the term. This keeps payments lower, but the full loan must be repaid at the end, separately, as our guide to interest-only buy-to-let explains. You therefore need a credible plan to repay the capital, such as savings, investments or selling the property.
The pros and cons of repayment
Repayment's main advantage is that you steadily clear the loan and own the home outright by the end, with no separate repayment to arrange and less reliance on the property's value. The trade-off is higher monthly payments than interest-only, since you are paying off capital too. For most homeowners, the certainty of clearing the mortgage makes repayment the sensible and usual choice.
The pros and cons of interest-only
Interest-only keeps monthly payments lower, freeing up cash, which is why it is common in buy-to-let to maximise rental profit. The drawbacks are significant: you build no equity through payments, owe the full loan at the end, and must have a repayment plan. For residential borrowers, interest-only is now much less common and requires a credible repayment strategy that lenders will scrutinise carefully.
Interest-only for residential versus buy-to-let
Interest-only is now relatively rare for residential mortgages, where lenders require a solid repayment plan and often stricter criteria, but it is the norm for buy-to-let, where landlords prioritise cash flow and usually plan to repay by selling, as our guide to the way mortgages work explains. So the structure that suits you depends partly on whether the property is your home or an investment.
Part-and-part mortgages
Some borrowers use a part-and-part mortgage, with one portion on repayment and the other interest-only. This reduces payments compared with full repayment while still clearing some of the loan and building some equity. It can be a middle path for those who want lower payments but are uneasy about owing the full amount at the end. Whether it suits you depends on your finances and plans.
An example of each
On a £200,000 mortgage at 5% over 25 years, a repayment mortgage might cost around £1,170 a month, gradually clearing the loan, while an interest-only version would cost about £833 a month but leave the full £200,000 owed at the end. The repayment option costs more monthly but clears the debt; the interest-only option is cheaper monthly but leaves a large sum to repay separately.
How the balance changes
With a repayment mortgage, the balance falls slowly at first, as early payments are mostly interest, then faster over time as more goes to capital. With interest-only, the balance does not change at all, staying at the original amount throughout. This difference means a repayment borrower builds equity steadily, while an interest-only borrower relies on other means, usually selling, to clear the loan at the end.
Switching between them
It is sometimes possible to switch between repayment and interest-only, subject to the lender's agreement and criteria. Moving from interest-only to repayment increases payments but starts clearing the loan, while the reverse lowers payments but stops reducing the balance. Lenders scrutinise switches to interest-only carefully, especially for residential mortgages, so it is not guaranteed. Discussing options with your lender or a broker helps you understand what is possible.
Affordability and structure
The structure affects affordability assessments. Interest-only has lower payments, but lenders apply strict criteria and require a credible repayment plan, so it is not simply an easy way to borrow more. Repayment is assessed on the higher payments that clear the loan. Understanding how the structure interacts with affordability helps explain why residential interest-only is now limited and carefully controlled, as our guide to what you can borrow notes.
Why residential interest-only is rare now
Residential interest-only mortgages became much less common after past concerns that some borrowers reached the end of their term without a way to repay the capital. Lenders now require solid repayment plans and apply strict criteria, so they are limited. Buy-to-let, by contrast, remains predominantly interest-only, since landlords plan to repay by selling. This is why the structure that suits you depends heavily on whether the property is your home or an investment.
Building equity versus keeping cash
The core trade-off is between building equity and keeping cash. Repayment steadily builds your ownership of the home and clears the debt, giving long-term security, while interest-only keeps monthly costs down and cash free, but leaves the debt in place. Which matters more, owning outright over time or maximising monthly cash flow, depends on your goals, and for a home, building equity is usually the priority.
Which suits a home versus an investment
For your own home, repayment is usually the right choice, since clearing the mortgage and owning outright gives security, and interest-only is now rare and tightly controlled for residential borrowers. For a buy-to-let investment, interest-only is common, prioritising rental cash flow with repayment planned through sale, as our guide to interest-only buy-to-let explains. So the property's purpose largely guides which structure suits.
For the great majority of homeowners, a repayment mortgage is the natural choice, steadily turning monthly payments into ownership, while interest-only remains mainly the preserve of buy-to-let investors with a clear plan to repay the capital when the property is eventually sold.
Whichever route applies to you, the essential point is to know which structure your mortgage uses and, if it is interest-only, to keep a realistic plan for repaying the capital firmly in view throughout the term.
In short
A repayment mortgage clears the loan by the end of the term, building ownership but with higher monthly payments, and is the usual choice for homeowners. An interest-only mortgage keeps payments low but leaves the full loan to repay separately, common in buy-to-let but now rare for residential and requiring a solid repayment plan. A part-and-part mortgage blends the two. The right structure depends on your goals and circumstances.
Where to get help and next steps
Read our guides to how mortgages work, interest-only buy-to-let, and the mortgage term. This is general information, not mortgage or financial advice.