Estimate monthly UK mortgage payments, loan-to-value, total interest and the effect of a 2 percentage-point rate increase.
Enter your mortgage details
Enter the property price, deposit, interest rate and term.
What is the United Kingdom Mortgage Calculator?
The United Kingdom Mortgage Calculator estimates payments for a capital repayment or interest-only mortgage. It subtracts your deposit from the property price, calculates the loan-to-value ratio, and shows the monthly payment, total interest and total amount repaid across the selected term.
The extra stress result shows an illustrative payment if the annual rate were 2 percentage points higher. It can help you see how sensitive the payment may be to a future rate change, but it is not a lender affordability assessment.
How to use the mortgage calculator
- Enter the property purchase price.
- Enter the cash deposit.
- Add the annual interest rate offered or being considered.
- Choose a term from 1 to 40 years.
- Select capital repayment or interest-only and press Calculate Mortgage.
Repayment mortgage formula
Here, P is the amount borrowed, r is the monthly interest rate and n is the number of monthly payments. If the interest rate is 0%, the loan is divided equally across the number of months.
With a repayment mortgage, each payment contains interest and a contribution towards the loan balance. Early payments normally contain a larger interest share, while later payments contain more capital.
Interest-only mortgage calculation
For an interest-only mortgage, the estimated monthly payment is the loan amount multiplied by the annual rate and divided by 12. The capital borrowed is not reduced by these monthly payments, so the full loan is assumed to be repaid separately at the end of the term.
Worked example
Suppose a property costs £300,000 and the deposit is £30,000. The mortgage is £270,000 and the LTV is 90%. At an illustrative 4.5% annual rate over 25 years on a repayment basis, the estimated monthly payment is approximately £1,500.75. Total repayments are approximately £450,224.31, including about £180,224.31 of interest, assuming the rate stays unchanged throughout the full term.
What does LTV mean?
Loan-to-value is the mortgage amount as a percentage of the property price. A £270,000 mortgage on a £300,000 property has a 90% LTV. A larger deposit produces a lower LTV. Mortgage product availability and pricing can vary by LTV band, lender rules, property type, credit history and affordability.
What this estimate does not include
- Arrangement, booking, valuation, legal or broker fees
- Stamp Duty Land Tax, LBTT or Welsh Land Transaction Tax
- Insurance, service charges, ground rent, repairs or moving costs
- Introductory rates changing after a fixed or discounted period
- Overpayments, payment holidays or early repayment charges
- Lender-specific affordability and credit checks
Important mortgage guidance
A mortgage is secured against your home. Missing payments can put the property at risk. Compare the total cost, product fees, reversion rate and any early repayment charge—not only the initial monthly payment. If the mortgage has a variable rate, check whether your budget could absorb an increase.
Related UK calculators
Frequently asked questions
Does this calculator include mortgage fees?
No. Arrangement, valuation, legal, broker and other property-buying costs are excluded.
Can I calculate an interest-only mortgage?
Yes. Select interest-only to estimate monthly interest and the total cost assuming the capital is repaid at the end.
What is the mortgage stress payment?
It is an illustration using an interest rate 2 percentage points above the rate entered.
Does the calculator show how much I can borrow?
No. It calculates payments for an entered property price and deposit. A lender decides borrowing capacity using its affordability and credit rules.
Will my actual monthly payment match exactly?
Not always. Lender rounding, fees, rate changes, payment dates and product conditions can create differences.
Important: Results are estimates and not a mortgage offer, affordability decision or financial advice.