Amortisation Calculator — UK
Generate a full monthly and yearly repayment schedule for any UK loan or mortgage in pounds sterling.
Enter loan details to generate amortisation schedule
Amortisation Calculator UK — See Every Repayment from Day One to Payoff
An amortisation schedule shows you exactly how each monthly repayment on your UK loan or mortgage is split between repaying the capital (the amount borrowed) and paying interest. In the early years of a repayment mortgage, the majority of each payment goes towards interest. Over time, this reverses — by the final years, nearly all of your payment reduces the outstanding balance. This calculator generates that full schedule instantly.
Understanding your amortisation schedule is particularly valuable when considering mortgage overpayments or remortgaging. For example, on a £200,000 repayment mortgage at 5% over 25 years, your total repayment is over £350,000 — £150,000 in interest alone. Seeing this laid out month-by-month motivates many UK borrowers to overpay and save significantly on total interest costs.
What is Amortisation?
Amortisation is the process of paying off a loan through regular fixed repayments over time. Each repayment covers both interest (charged on the outstanding balance) and capital (reducing the balance). As the outstanding balance decreases, less interest is charged each month, meaning more of your fixed repayment goes towards the capital.
- UK repayment mortgages are fully amortising — you are guaranteed to have repaid the loan in full by the end of the term if you make every payment on time.
- Interest-only mortgages are not amortising — your monthly payment covers only the interest, and the full capital balance remains at the end of the term.
- The amortisation schedule assumes a fixed interest rate. For tracker or variable-rate mortgages, your actual payments will differ if rates change.
- Making overpayments accelerates amortisation — each overpayment reduces the outstanding balance and therefore the interest charged in all future months.
How to Use This Calculator
- Enter the Loan Amount in pounds (e.g., £200,000 for a mortgage or £15,000 for a personal loan).
- Enter the Annual Interest Rate — use your current rate or the rate quoted for a new loan (e.g., 5.0%).
- Set the Loan Term in years and/or months (e.g., 25 years for a mortgage).
- Optionally set a Start Date to generate a dated schedule.
- Click Calculate to view your full amortisation schedule, switchable between monthly and yearly views.
Amortisation Formula
- P = Principal (loan amount)
- r = Monthly rate = Annual rate ÷ 12 ÷ 100
- n = Total months
- Example: £200,000 mortgage at 5% over 25 years (300 months)
- Monthly Repayment = £1,169/month
- Total Repaid = £350,700 | Total Interest = £150,700
Key Terms
- Repayment Mortgage
- The most common UK mortgage type — each monthly payment reduces both the outstanding capital and pays the interest. At the end of the term, the mortgage is fully repaid. Lenders and regulators consider this the standard, lower-risk mortgage structure.
- Interest-Only Mortgage
- A mortgage where monthly payments cover only the interest charge — the full capital balance remains at the end of the term and must be repaid in full (e.g., from sale of the property or a savings vehicle). Interest-only mortgages are less common for residential borrowers following post-2008 FCA reforms but are used in buy-to-let lending.
- Outstanding Balance
- The remaining capital owed on your loan or mortgage at any point in time. Each repayment reduces this figure (on a repayment mortgage). You can request an outstanding balance statement from your lender at any time — this is needed to calculate overpayment headroom or a settlement figure.
- Mortgage Statement
- An annual document sent by UK mortgage lenders showing your outstanding balance, interest charged, and payments made during the year. Since 2016, lenders must also show the total cost of your mortgage to date and the projected total cost. Review your statement yearly to track progress.
- Capital Repayment
- The portion of your monthly payment that reduces the outstanding balance. In the early months of a 25-year mortgage, capital repayment can be as little as 20%–30% of your payment — the rest is interest. By year 20, this reverses. The amortisation schedule shows this split for every month.
Tips for UK Mortgage Holders
- Use the yearly view to quickly see how your outstanding balance reduces — this helps you plan when you'll reach a better LTV band for remortgaging.
- Compare your amortisation schedule at different rates before remortgaging — even 0.5% difference on a £200,000 mortgage saves over £15,000 in total interest over 25 years.
- If you're considering an interest-only mortgage, use this calculator to compare it against a repayment mortgage — the capital debt doesn't reduce on interest-only, which can be a significant risk.
- Your amortisation schedule changes if rates change (tracker/SVR mortgages) — recalculate whenever your rate is updated.
- Lenders must provide a Key Facts Illustration (KFI) showing the total cost of your mortgage — your amortisation schedule helps you verify these figures.
- Consider sharing the schedule with a mortgage adviser — seeing the long-term interest cost in full often reveals worthwhile overpayment or remortgage opportunities.
Frequently Asked Questions
A repayment mortgage reduces both the capital and interest each month — you're guaranteed to own your home outright at the end of the term. An interest-only mortgage only covers the interest each month — the full loan amount remains at the end and must be repaid separately (usually through selling the property or a savings/investment vehicle). Repayment mortgages are the standard for UK residential buyers; interest-only is more common in buy-to-let.
Every overpayment directly reduces your outstanding balance, which means less interest is charged in every subsequent month. This shortens the overall term. For example, on a £200,000 mortgage at 5% over 25 years, overpaying £200/month from the start reduces the term by over 6 years and saves over £27,000 in interest. Use the mortgage overpayment calculator alongside this tool for a precise comparison.
Interest is calculated on the outstanding balance each month. At the start, your balance is at its highest — so more of your fixed payment goes to cover the interest charge, leaving less to reduce the capital. As the balance reduces over time, less interest accrues each month and more of your payment reduces the capital. This is the nature of amortisation and is why early overpayments have the greatest long-term impact.
Your outstanding balance is shown on your annual mortgage statement, which UK lenders are required to send each year. You can also check it via your lender's online banking portal or app. If you need a precise figure for remortgaging or overpayment planning, ask your lender for a current statement — they must provide this under the Mortgage Credit Directive. Note that the balance changes each month as you make repayments.
Yes — enter your buy-to-let mortgage balance, interest rate, and remaining term to generate the schedule. Note that most UK buy-to-let mortgages are interest-only, meaning your capital balance doesn't reduce. If yours is interest-only, the schedule will show your monthly interest cost but the outstanding balance will remain constant. For tax purposes, UK landlords should consult an accountant regarding mortgage interest relief changes under Section 24.
When you remortgage, a new amortisation schedule begins based on your outstanding balance at that point, the new interest rate, and the remaining term (or a new term if you extend). If you remortgage to a lower rate without extending the term, your monthly payment decreases and you pay less total interest. If you extend the term to reduce monthly payments, you pay more total interest overall — the schedule makes this trade-off clear.