UK Interest-Only Mortgage Payment Calculator
Estimate your interest-only mortgage payments in seconds. Enter your mortgage amount, rate, and term to see your likely payment and total interest cost.
Estimated monthly payment: £0.00
Estimated annual interest: £0.00
Total interest over term: £0.00
Balance remaining at end of term: £0.00
Equivalent repayment mortgage (monthly): £0.00
Illustration only. Actual payments can change with variable rates, fees, lender terms, and product structure.
What is an interest-only mortgage in the UK?
An interest-only mortgage means your regular payments cover only the interest charged by the lender. Your loan balance (the capital) usually does not reduce during the term. At the end of the mortgage term, you still owe the original amount borrowed and must repay it in full.
This can keep monthly payments lower than a repayment mortgage, but it also means you need a clear and realistic repayment plan for the capital. UK lenders often ask for evidence of that plan before approving an interest-only deal.
How to use this interest-only mortgage payment calculator uk
- Mortgage amount: Enter the total loan you want to borrow (not property price).
- Interest rate: Use your lender's annual rate (fixed, variable, or tracker estimate).
- Term: Enter the number of years for the mortgage term.
- Frequency: Choose monthly, fortnightly, quarterly, or annual payment view.
The calculator then estimates your payment, yearly interest cost, full-term interest (assuming the rate stays the same), and the remaining balance due at the end of the term.
How the calculator works
Interest-only payment formula
Annual interest = Loan amount × (Interest rate ÷ 100)
Periodic payment = Annual interest ÷ number of payment periods in a year
Total interest over the full term
Total interest = Annual interest × Mortgage term in years
Because this is interest-only, the capital is not automatically paid down through your regular payment.
Interest-only vs repayment mortgage
A repayment mortgage includes both interest and capital in each monthly payment, so the balance gradually falls. An interest-only mortgage usually has lower monthly payments, but the capital remains outstanding.
- Interest-only: Lower monthly payments, higher end-of-term repayment risk.
- Repayment: Higher monthly payments, balance normally reaches £0 at term end.
This page also shows a repayment mortgage monthly estimate for comparison, using the same amount, term, and rate.
What this calculator includes and does not include
Included
- Estimated interest-only periodic payment
- Annual interest estimate
- Total interest over full term (constant-rate assumption)
- End-of-term balance due
Not included
- Arrangement fees, broker fees, valuation fees, legal fees
- Early repayment charges
- Insurance (buildings, life cover, income protection)
- Future rate changes on variable/tracker products
- Tax effects for buy-to-let borrowers
Common UK repayment vehicles for interest-only mortgages
If you choose interest-only, you usually need a plan to repay the capital at the end. Common options include:
- Sale of the mortgaged property
- Sale of another property
- Stocks and shares ISA or investment portfolio
- Pension lump sum (where appropriate)
- Endowment or other long-term savings plan
Important risks to understand
- Investment returns may underperform your target.
- Property prices can fall, reducing sale proceeds.
- Variable rates can increase payments materially.
- You could reach term end with a repayment shortfall.
Always review affordability under higher-rate scenarios and consider independent mortgage advice before committing.
Frequently asked questions
Is an interest-only mortgage always cheaper?
Monthly payments are usually lower, but overall cost can be higher because the capital is not reduced over time.
Can first-time buyers get interest-only mortgages in the UK?
Some lenders allow it, but criteria are often stricter, including income, loan-to-value limits, and repayment strategy evidence.
Do I still owe the full mortgage amount at the end?
In most interest-only setups, yes. You are responsible for repaying the full original capital at term end.
Is this calculator a mortgage offer?
No. It is an educational estimate, not a formal quotation, recommendation, or financial advice.
Bottom line
This interest only mortgage payment calculator uk helps you quickly estimate costs and compare interest-only against repayment. Use it to plan, stress-test your budget, and decide whether an interest-only structure truly fits your long-term strategy.