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Compare · Interest-only mortgage vs Repayment mortgage

Interest-only vs repayment mortgage — what's the difference?

In short. On a repayment mortgage your monthly payment covers interest and chips away at the capital, so the loan is cleared at the end. On interest-only you only pay the interest each month — the full capital is still owed at the end of the term.

Repayment is the standard for residential mortgages in the UK. Interest-only is more common in buy-to-let, but is sometimes available for residential borrowers with a credible repayment strategy. The choice changes monthly affordability and the total amount you pay.

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Side by side

CriterionInterest-only mortgageRepayment mortgage
Monthly paymentLower (just interest)Higher (interest + capital)
Balance at end of termFull original loan still owedZero (loan paid off)
Total interest paidHigher (capital doesn't reduce)Lower (capital shrinks each month)
Repayment vehicle requiredYes — must be agreed at the start (ISA, pension lump sum, sale of property, savings)Not required — repayment is built in
Typical useBuy-to-let, some high-net-worth lendingStandard residential mortgage
FCA affordability rulesStricter — credible repayment plan must be evidencedStandard MMR/affordability checks

When Interest-only mortgage usually wins

  • You're a buy-to-let landlord using rental income to service interest
  • You have a credible repayment vehicle and want lower monthly outgoings
  • Your income is variable and you want minimum required payments
  • You expect to sell the property to clear the balance

When Repayment mortgage usually wins

  • You want certainty of clearing the mortgage by retirement
  • You're a typical residential first-time buyer or homeowner
  • You prefer paying less interest overall
  • You don't have a separate investment plan to repay the capital

FAQ

Can I mix interest-only and repayment?
Yes — some lenders offer 'part-and-part' mortgages where part of the loan is interest-only and the rest is on repayment.
What happens at the end of an interest-only term if I can't repay?
You'd need to refinance, sell the property, or agree another arrangement with the lender. The FCA has been working with lenders to help borrowers facing maturity shortfalls — contact your lender as early as possible.
Is interest-only cheaper overall?
No — because the capital never reduces, you pay interest on the full balance every month. Total interest paid is usually significantly higher than on a repayment mortgage of the same rate and term.