InstalmentLoans

Loan Payment Calculator

A loan payment calculator shows what you will repay each month on a fixed-rate instalment loan. Enter the amount, representative APR and term to see the monthly repayment, the total interest and the total amount repayable.

By the InstalmentLoans Editorial Team · Last updated 2 October 2026

Get an instalment loan quote Check the repayment first

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WARNING: Late repayment can cause you serious money problems. For help, go to moneyhelper.org.uk

Enter your numbers and press Calculate. Nothing you type leaves your browser.

How this calculator works

This calculator answers one question: what will the monthly repayment be? It uses the same repayment formula lenders use for fixed-rate instalment loans.

M = P * r * (1 + r)^n / ((1 + r)^n - 1)

A longer term lowers the monthly repayment but raises total interest, because you pay interest for more months. A shorter term does the opposite.

Enter your own rate. Rates vary by lender and credit profile, so the result is an estimate and not a quote.

Frequently asked questions

What is the difference between the repayment and the total cost?
The monthly repayment is what you pay each month. The total cost is every repayment added together, which includes the interest paid on top of the amount borrowed.
Can I use this for a car loan or a larger loan?
Yes. Any fixed-rate instalment loan with equal monthly payments works with this formula. Dedicated tools for car finance and overpayments add fields such as a deposit or an extra monthly amount.
What happens if the interest rate is 0%?
The formula simplifies to P / n, so the repayment is the amount borrowed divided by the number of months. Total interest is zero.
Does a lower repayment always mean a cheaper loan?
No. A lower repayment often comes from a longer term, which means more months of interest. Compare the total cost of credit as well as the monthly repayment.

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