Mortgage calculator

Using this tool thoughtfully

Tool notes & guidance

How to use this tool

Choose a currency and mortgage type. Enter the property price and cash deposit; the loan is their difference.
Enter your own annual nominal rate and term. Add an optional monthly overpayment for repayment mortgages only.
Review the monthly payment, interest, final capital payment and annual schedule. Compare the lender’s actual illustration and charges.

How mortgage repayments are estimated

Loan, term and rate

The loan is property price minus deposit. The term is whole years × 12 months. We use the annual nominal interest rate divided by 12. For repayment mortgages the monthly payment is P × r ÷ (1 − (1+r)⁻ⁿ), where P is the loan, r is the monthly rate and n is the number of payments. At zero interest the payment is P ÷ n.

Rounding and repayment schedule

Scheduled payments and each month’s interest are rounded to two decimal places. Each payment covers interest first, then reduces capital. Overpayments start with the first monthly payment and keep the original scheduled payment; they reduce the term rather than recalculate the payment. The final payment is adjusted to clear the remaining balance. Annual rows reconcile payments, capital, interest and closing balance.

Interest-only capital at the end

The regular monthly amount is the loan × annual rate ÷ 12. The loan capital remains outstanding throughout the term and must be paid separately at the end. The total shown includes that final capital payment. This model does not simulate mixed repayment/interest-only loans.

Assumptions and excluded costs

The rate remains constant for the full term, even when a real introductory fix expires earlier. No arrangement fees, early repayment charges, property taxes, insurance or currency conversion are included. Daily interest, payment dates and provider rounding can change the actual figures. This estimate does not determine affordability, lending eligibility or a product recommendation.

Islamic home finance

Islamic home-purchase plans have contractual ownership, rental, purchase and fee arrangements. This conventional interest calculation is not a quotation or certification for one of those plans. Obtain the provider’s payment illustration and qualified religious advice for the particular contract. See the MoneyHelper home-purchase-plan reference below.

Common questions

Does a longer term reduce the cost?

A longer repayment term normally lowers the regular payment but increases total interest at the same positive rate. Compare both figures, not just the monthly amount.

What does an overpayment change?

This model adds the same extra payment each month, keeping the scheduled repayment amount. It estimates an earlier payoff and interest savings versus the same loan without extra payments. Check charges and limits in the actual contract.

Is the interest-only figure the full cost?

No. It is the regular interest payment only. The full loan capital is still due separately at the end, and the result shows it explicitly.

Can I use this to price an Islamic mortgage?

Not as an Islamic finance quote. Use the provider’s contractual payment and rental schedule; conventional interest amortisation does not establish the cost or compliance of a home-purchase plan.

Sources & review status

Read the calculation method and limits and editorial standards and review status. These educational tools have not been independently certified by a scholar.

Mortgage calculator