Loan Repayment Calculator
Find out your monthly repayment, total interest, and total cost of borrowing in seconds — for personal loans, car finance, or any fixed-rate loan.
Work Out Your Monthly Repayments
Enter your loan amount, interest rate, and term below. The calculator updates instantly and shows your monthly payment alongside the total interest and total amount you’ll repay over the life of the loan.
Your Repayment Summary
Updates automatically as you change the form
How Loan Repayments Are Calculated
This calculator uses the standard amortising loan formula that most personal loans and car finance agreements are based on, splitting each payment between interest and capital.
Convert the Annual Rate to a Monthly Rate
Your annual interest rate (APR) is divided by 12 to get the monthly rate applied to your outstanding balance each month.
Calculate the Fixed Monthly Payment
Using the loan amount, the monthly rate, and the number of months in the term, the calculator works out a single fixed payment that clears the loan by the end of the term.
Split Each Payment Between Interest and Capital
Early payments are weighted more towards interest, since the outstanding balance is highest. As the balance falls, more of each payment goes towards clearing the capital.
Apply Any Overpayments
Adding an extra amount to your monthly payment reduces the capital faster, which lowers future interest charges and can shorten how long the loan takes to repay in full.
Fixed vs Variable Rate Loans
Before you borrow, it’s worth knowing how the two main types of interest rate affect your repayments.
| Feature | Fixed Rate Loan | Variable Rate Loan |
|---|---|---|
| How it works | Interest rate stays the same for the whole term. | Interest rate can rise or fall with the lender’s base rate. |
| Monthly payment | Identical every month, easy to budget for. | Can change over time, sometimes with little notice. |
| Best for | Borrowers who want certainty over the full term. | Borrowers comfortable with some payment fluctuation. |
| Overpayment charges | More likely to apply early repayment charges. | Often more flexible on overpayments. |
| Typical use | Personal loans, car finance, fixed-rate mortgages. | Some mortgages, credit cards, overdrafts. |
Loan Repayment FAQ
Answers to the questions borrowers ask most often about working out and managing loan repayments.
A monthly loan repayment is calculated using the loan amount, the annual interest rate converted to a monthly rate, and the number of months in the term. Each fixed monthly payment covers that month’s interest first, with the remainder reducing the outstanding balance, so the interest portion falls and the capital portion rises over the life of the loan.
The interest rate is the cost of borrowing the capital itself, while APR (Annual Percentage Rate) also includes most mandatory fees and charges, giving a more complete picture of the true yearly cost. Two loans with the same interest rate can have different APRs if one carries higher arrangement or admin fees.
Yes, any overpayment reduces the outstanding capital immediately, which lowers the interest charged in every following month and can shorten the loan term. Check your loan agreement first, since some fixed-rate loans charge an early repayment fee on overpayments above a set limit.
Missing a repayment usually triggers a late payment fee and is reported to credit reference agencies, which can lower your credit score and make future borrowing more expensive. Interest typically continues to accrue on the outstanding balance, so a missed payment can also extend how long the loan takes to clear.