Loan Repayment Calculator
Before taking on a loan, it helps to know the monthly cost. Enter the amount you want to borrow, the annual interest rate, and the term in years to see your estimated monthly repayment.
Note: Assumes a fixed rate and standard amortisation. Real loans may include fees, variable rates, or insurance.
How this calculator works
This uses the standard amortising loan formula. It takes the monthly interest rate (the annual rate divided by twelve), applies it across the full number of monthly payments, and solves for the fixed monthly amount that pays off both the interest and the original balance by the end of the term. Early payments are mostly interest; later ones are mostly principal, but the monthly figure stays the same throughout.
Worked example
Borrow $200,000 at 5% annual interest over 25 years. The monthly rate is about 0.417%, spread over 300 payments. The formula gives a monthly repayment of roughly $1,169. Over the full term you would repay about $350,000, of which around $150,000 is interest.
Frequently asked questions
Does this include fees or insurance?
No. It shows principal and interest only. Real mortgages may add arrangement fees, property insurance, or taxes, so your actual monthly outgoing can be higher.
What happens if interest rates change?
This assumes a fixed rate for the whole term. On a variable-rate loan, your monthly payment will rise or fall as the rate changes.
How can I reduce the total interest I pay?
Choosing a shorter term or making overpayments reduces the interest substantially, because you spend less time being charged interest on the balance.