Repayment vs Interest-Only
Compare repayment and interest-only mortgages side by side for any UK property. See the monthly payment difference, total interest cost over the full term, and how much equity you actually own at the end — the gap in lifetime interest paid is usually far larger than expected.
How do the two types compare?
Balance remaining over term Repayment Interest-only
Repayment mortgage reduces the balance to zero by end of term. Interest-only keeps the balance flat — the full loan remains outstanding on day one of year 26 (or whatever term you choose).
What to bear in mind
Interest-only only makes sense with a credible repayment vehicle — such as an endowment policy, stocks and shares ISA, or investment portfolio — that is on track to repay the full capital at the end of term. Most mainstream lenders require proof of a repayment vehicle before approving interest-only. The key risk: if the investment underperforms, you may not have enough to repay the loan at the end of term and could be forced to sell the property.
Mortgage brokers worth considering
Disclosure: links below are affiliate links — we may earn a commission at no cost to you. We only list providers we'd genuinely consider.
One of the UK's largest fee-free mortgage brokers. Searches thousands of deals across the whole market. Particularly strong for first-time buyers and remortgages.
Online-firstDigital mortgage broker that handles the whole process online. Good for repayment mortgages and straightforward cases. Habito One offers a long-term fixed rate.
Specialist casesOnline brokers offering access to a wide panel of lenders, including some that offer interest-only products. Useful if your situation doesn't fit the mainstream.
Use our mortgage comparison calculator to model different rates and terms before you speak to a broker.
Repayment vs interest-only: what every borrower should know
Most UK mortgages are repayment (also called capital and interest). Each month you pay both the interest charge and a portion of the original capital. By the end of the term, the debt is gone. Interest-only works differently: your monthly payment covers only the interest, and the original loan balance stays exactly the same until the final day of the mortgage. At that point, you must repay the full capital in one go.
Why interest-only looks attractive
The monthly payment on an interest-only mortgage is always lower than a repayment mortgage on the same balance and rate. On a £250,000 mortgage at 4.5% over 25 years, a repayment mortgage costs around £1,389/month while interest-only costs just £938/month — a monthly saving of over £450. For landlords and investors, that lower outgoing can make the numbers work on a buy-to-let where rents are tight.
The hidden cost of interest-only
The monthly saving comes at a price. With a repayment mortgage, you gradually build equity — the amount of the property you own outright — every single month. Every payment chips away at the debt. With interest-only, the full balance is still there on day one of year 26. You've paid hundreds of thousands of pounds in interest, but not reduced the debt by a single pound.
How lenders view interest-only today
After the 2008 financial crisis exposed millions of borrowers with no plan to repay their interest-only loans, lenders significantly tightened criteria. Today, most mainstream residential lenders require a formal repayment vehicle — and evidence it will generate sufficient funds — before approving an interest-only mortgage. Common acceptable vehicles include: a stocks and shares ISA, an endowment policy, a pension lump sum, or the sale of another property. Pure "house price growth" is no longer accepted.
When interest-only does make sense
Buy-to-let mortgages are predominantly interest-only — landlords prefer the lower monthly outgoings and manage capital repayment through eventual property sale. Interest-only can also make sense for high-earning professionals with variable income who want to keep monthly commitments low while investing separately — provided the investment discipline is genuine, not aspirational. Some bridging loans and short-term property finance products are interest-only by design.
The part-and-part option
Some lenders offer a hybrid sometimes called "part-and-part" — where a portion of the mortgage is repayment and the rest is interest-only. This gives a lower monthly payment than full repayment while building some equity. It can be a pragmatic middle ground for borrowers who need to manage cashflow but want to avoid the full risk of the interest-only route.
One practical rule
If you're considering interest-only, ask yourself: where is the money to repay the capital coming from, and is it watertight? If the answer is "property price growth" or "I'll figure it out in 25 years", that's a risk most financial advisers would flag. If you have a concrete, funded repayment vehicle that's on track, the lower monthly payment can genuinely be the right choice. If you don't, a repayment mortgage is almost always the safer and ultimately less expensive option over a lifetime.
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