Loan Overpayments Explained (UK): How Extra Payments Reduce Interest
Overpaying a loan can reduce total interest and shorten your repayment term. The impact depends on your rate, remaining term, and whether early repayment charges apply.
This guide explains how overpayments work in the UK, when they are effective, and how to model the savings realistically.
Why overpayments reduce interest
Interest is charged on the remaining balance.
Loans charge interest on the outstanding principal. When you make an overpayment, you reduce the principal earlier than scheduled. Because future interest is calculated on a smaller balance, total interest falls.
The earlier you overpay, the larger the interest saving typically becomes. This is because more months remain in which interest would otherwise accrue.
When overpayments make sense
Overpayments are usually most effective when:
- Your loan has no early repayment charge.
- The interest rate is higher than the return you would earn elsewhere.
- You already have an emergency buffer.
If early repayment charges apply, compare the cost of the charge against projected interest savings before deciding.
Worked example (illustrative)
Assume a £10,000 loan at 8% APR over 5 years. Adding £50 per month in overpayments could reduce total interest and shorten the term. Exact figures depend on amortisation rules and rounding, so use a calculator to estimate your specific savings.
Last updated: 1 March 2026