Loan Payment Calculator

Enter the loan amount, interest rate and term — see your monthly payment, total cost and principal vs interest breakdown instantly.

£
%
Monthly payment
Total cost
Total interest

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Find a better rate by comparing current offers.

Estimates only. Actual APR, fees and insurance are set by the lender's agreement.

How the loan payment calculator works

Enter the loan amount (how much you want to borrow), the annual interest rate (use the nominal rate, not APR), and the loan term in years or months. The monthly payment, total repayment and interest update in real time as you type.

The donut chart shows the split between principal (what you borrowed) and interest (the cost of borrowing). The lower the rate and the shorter the term, the smaller the interest slice. On a 25-year mortgage the interest can easily exceed the original principal — the chart makes this visible at a glance.

The maths behind the result

  • Monthly payment = P × r × (1+r)ⁿ / ((1+r)ⁿ − 1)
  • P = loan amount · r = annual rate ÷ 12 ÷ 100 · n = number of monthly payments
  • Total cost = monthly payment × n · Total interest = total cost − P

Frequently asked questions

How is the monthly payment calculated?

Using the annuity (equal-payment) formula: payment = P × r × (1+r)ⁿ / ((1+r)ⁿ − 1), where P is the principal, r is the monthly rate (annual rate ÷ 12) and n is the number of monthly payments.

Does it include fees and insurance?

No — the calculator uses only the loan amount and nominal interest rate. APR (which includes fees, insurance and other charges) varies by lender and is stated in the loan agreement.

Is my data sent anywhere?

No. Everything runs locally in your browser — no figures are transmitted to any server.

What is a typical personal loan rate in the UK?

Representative APRs for UK personal loans in 2024/25 range from about 6% (for prime borrowers, £7,500–£15,000) to 40%+ for smaller or bad-credit loans. The average for £10,000 over 5 years is roughly 7–9% APR.

How to calculate your monthly loan payment

Your monthly loan payment depends on three things: the amount you borrow (the principal), the interest rate, and the length of the loan (the term). A longer term lowers the monthly payment but increases the total interest you pay overall.

Enter different amounts, rates and terms above to see how each one changes your monthly payment and the total cost of the loan.