See your full loan amortisation schedule, total interest, and how extra payments shorten your payoff time.
Rates as of Q2 2025 (example)
| Period | Date | Payment | Principal | Interest | Balance |
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An amortisation calculator breaks down a loan into its full repayment schedule, showing exactly how much of each monthly payment goes toward interest versus reducing the loan balance (principal), and how that split changes over the life of the loan. It also shows how making extra monthly payments can shorten your loan term and reduce the total interest you pay.
Each monthly payment is split between interest (calculated on the current outstanding balance) and principal (which reduces the balance). Early in the loan, most of each payment goes toward interest because the balance is highest; as the balance falls, a larger share of each payment goes toward principal — even though the total monthly payment stays the same for a fixed-rate loan.
Formula: Monthly Payment = [Loan Amount × r × (1+r)n] / [(1+r)n − 1], where r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the total number of monthly payments. For each month: Interest = Outstanding Balance × r, and Principal Paid = Monthly Payment − Interest.
Example: For a £200,000 loan at a 5.5% interest rate (example rate — enter your actual rate) over 25 years, the monthly payment is roughly £1,228, with total interest of about £168,500 over the full term — meaning the total amount repaid is roughly £368,500. In the first month, most of that £1,228 payment goes toward interest; by the final year, almost all of it goes toward principal. (Note: all figures in this example are for illustration purposes only.)
Amortisation schedules apply to most fixed-term repayment loans in the UK, including mortgages, personal loans, and car finance — any loan where you make equal regular payments that gradually pay off both interest and principal. Understanding your amortisation schedule can be useful for several reasons: it shows how much equity you're building in a property over time, how much interest you'll pay in total versus just looking at the monthly payment, and how the balance changes if you want to estimate an early settlement figure (though lenders may add fees for early repayment). For mortgages on fixed-rate deals, the amortisation schedule shown here assumes the rate stays constant for the full term — in practice, most UK mortgage holders remortgage onto a new rate when their fixed deal ends, which would restart the calculation with a new rate and remaining balance.
An amortisation schedule shows, for each payment period, how much of your payment goes toward interest and how much goes toward reducing the loan balance (principal), along with the remaining balance after each payment.
Interest is calculated on the outstanding balance, which is highest at the start of the loan. As the balance decreases over time, the interest portion of each payment shrinks and the principal portion grows, even though the total monthly payment stays the same.
No — the default is an example only. Interest rates vary by lender, loan type, and your personal circumstances. Enter the actual rate from your loan agreement or quote for an accurate schedule.
Extra payments go directly toward reducing the principal balance, which reduces the interest charged in future months. This compounds over time, often shortening the loan term significantly and reducing total interest paid — even relatively small extra payments can have a meaningful effect over a long term.
No. Some UK loans, particularly mortgages on fixed-rate deals, charge an early repayment fee if you pay off more than an allowed amount or settle the loan early. Check your loan agreement for any such charges, as they aren't included in this calculator.
Yes — the amortisation formula is the same for mortgages, personal loans, and car finance. For a mortgage-specific calculation that includes buildings insurance and service charges, use the Mortgage Calculator instead.
Disclaimer: The information, rates, and figures provided on this page are for educational and illustrative purposes only and do not constitute financial advice. The default interest rate is a sample value and does not reflect rates currently available from any specific lender. Loan terms, fees, and early repayment charges vary by lender and product. Always consult your loan agreement or a qualified financial adviser before making any financial decisions.