Use the calculator
How this calculator works
This calculator estimates the fixed monthly repayment on a loan that is paid off in equal instalments, like most UK personal loans and car loans. Enter the amount you want to borrow, the annual interest rate and the number of years.
It converts the annual rate into a monthly rate (the rate divided by 12) and uses the standard amortisation formula: repayment = amount × r ÷ (1 − (1 + r)−n), where r is the monthly rate and n is the number of monthly payments. Early repayments are mostly interest; later ones are mostly capital. It then shows the total you would repay over the term and how much of that is interest.
If you enter a rate of 0%, the calculator simply divides the amount by the number of months.
The calculator is most useful before you apply. Working out an affordable monthly figure first, then testing which amount and term produce it, helps you avoid borrowing more than you need or choosing a term only because it gives the lowest payment.
Worked examples
The figures below were produced by this calculator. They are illustrations, not quotes.
Example 1: £10,000 over 5 years at 8.9%
The monthly repayment is £207.10. Over 60 payments you repay £12,425.91, of which £2,425.91 is interest.
Example 2: the same £10,000 over 3 or 7 years
Over 3 years the repayment rises to £317.53 a month but total interest falls to £1,431.16. Over 7 years the repayment drops to £160.38 a month, but total interest rises to £3,472.23. Stretching the term from 3 to 7 years saves £157.15 a month but costs £2,041.07 more interest overall.
Example 3: £5,000 over 3 years at 6%
The repayment is £152.11 a month, and the total repaid is £5,475.95, including £475.95 of interest. Comparing this with Example 1 shows how both a smaller balance and a lower rate cut the interest bill.
Assumptions and what this calculator does not cover
- Rate type: it treats the rate you enter as a fixed nominal annual rate. Lenders advertise a representative APR, which includes compulsory fees and may be calculated differently; the rate you are actually offered depends on your credit history and can be higher than the advertised rate.
- Fees: arrangement fees, broker fees and payment-protection products are not added.
- Early repayment: overpayments and early settlement are not modelled. Settling a regulated loan early can involve a charge.
- Variable rates and mortgages: the calculator assumes the rate stays fixed for the full term. It is not designed for mortgages with introductory deals, interest-only loans or credit cards.
- Rounding: real loans round each payment to the penny, so the last payment may differ slightly.
Comparing loans fairly
When comparing offers, look at three numbers together: the monthly repayment, the total amount repayable and the APR. A loan with a lower monthly payment is not necessarily cheaper; it may simply run for longer. The total amount repayable shows the full cost of borrowing, and it is shown in the pre-contract information a lender must give you.
Try entering each offer into the calculator with its own rate and term. If an offer includes an arrangement fee, add it to the total repayable yourself, or compare APRs, which already include compulsory fees.
Before borrowing, check that the repayment fits comfortably in your budget with some room to spare, because the payment is fixed even if your income or other costs change. If the loan is to pay off other debts, compare the total interest of the new loan with what you would pay by keeping the existing debts, and read our guide to how loan repayments work.
Frequently asked questions
Is the interest rate the same as the APR?
Not always. The APR includes the interest rate plus compulsory fees, expressed as a yearly rate. For a loan with no fees the two are close. Use the rate you have actually been offered for the most realistic estimate; see our guide to APR versus interest rate.
Why does a longer term cost more?
You borrow the money for longer, so interest is charged on the outstanding balance for more months. Monthly repayments fall but the total interest rises, as the 3-year and 7-year examples above show.
Can I pay off a loan early?
Most personal loans can be repaid early, but the lender may charge a fee for early settlement. Ask the lender for a settlement figure before deciding.
Does the Bank of England base rate change my loan payments?
Not on a fixed-rate loan, where the rate is set for the term. New loan pricing tends to move with interest rates in the wider market, and variable-rate borrowing can change when Bank Rate changes.
What should I do if I am struggling with repayments?
Contact your lender early. GOV.UK lists options for paying off debts and free, confidential debt advice services.
Sources
Rates for tax year 2026/27, last reviewed October 2026.
Results are estimates for planning, not financial or tax advice. See our terms and methodology.