UK Mortgage Calculator
Work out your monthly mortgage repayments, the stamp duty on your purchase and how much cash you need upfront. Compare repayment with interest-only and see what overpaying saves.
Monthly payment
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Loan amount
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Total interest
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Total of payments
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Paid off
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Cash needed upfront
How the stamp duty is worked out
| Part of the price | Rate | Tax |
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Rates for England and Northern Ireland, checked October 2026. Scotland and Wales use their own taxes.Official rates on GOV.UK
Balance over time
Balance owedInterest paid so farPrincipal paid so far
Amortization schedule
| Year | Principal | Interest | Taxes & costs | Balance |
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How to use the UK mortgage calculator
Enter the property price, your deposit (as an amount or a percentage), the mortgage rate and the term. Choose a repayment or interest-only mortgage and the calculator shows your monthly repayment, the total interest, when the mortgage ends and your loan-to-value (LTV).
Stamp duty and cash upfront
Pick the type of buyer to work out Stamp Duty Land Tax for England and Northern Ireland, including first-time buyer relief and the surcharges for additional homes and non-UK residents. The calculator adds your deposit, stamp duty and fees to show the total cash you need to complete. Scotland (LBTT) and Wales (LTT) have their own rates.
Assumptions
One interest rate is used for the whole term. In practice most mortgages are fixed for two to five years and then move to the lender’s variable rate, so long-term totals are estimates. Results help you plan and compare; they aren’t a mortgage offer or financial advice. Speak to a mortgage adviser before you apply.
Frequently asked questions
How are monthly mortgage repayments worked out?
On a repayment mortgage each payment covers that month’s interest plus some of the loan, using M = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1). Borrowing £255,000 at 6% over 25 years costs £1,642.97 a month. On interest-only you pay just the interest, £1,275 a month, but still owe the full £255,000 at the end.
How much stamp duty will I pay?
In England and Northern Ireland, home movers pay nothing on the first £125,000, 2% up to £250,000, 5% up to £925,000, 10% up to £1.5 million and 12% above. First-time buyers pay nothing up to £300,000 and 5% up to £500,000, if the price is £500,000 or less. Additional homes pay 5% more on every band. Scotland and Wales have their own taxes (LBTT and LTT).
What is loan-to-value (LTV) and why does it matter?
LTV is the loan as a share of the property’s value. A £255,000 mortgage on a £300,000 home is 85% LTV. Lenders price deals in LTV bands such as 60%, 75%, 85%, 90% and 95%, so a bigger deposit usually gets a lower rate.
Can I overpay my mortgage?
Most fixed-rate deals let you overpay up to 10% of the balance each year without an early repayment charge. Overpaying cuts the interest you pay and can end the mortgage years early. Check your lender’s limit first.
What happens when my fixed rate ends?
You move to the lender’s standard variable rate, which is usually much higher. Most people remortgage to a new deal before that. This calculator uses one rate for the whole term, so treat long-term totals as an estimate.