UK Mortgage Calculator
Work out your monthly mortgage payment, total interest and loan-to-value for a repayment or interest-only mortgage.
Your mortgage
A £300,000 home with a £60,000 deposit means borrowing £240,000 (LTV 80%). At 5% over 25 years, that's £1,403/month — about £180,905 in interest over the term.
Show yearly breakdown — balance, principal & interest by year
| Year | Balance | Principal paid | Interest paid |
|---|
This is a standard amortisation calculation with no UK-specific thresholds. Interest rates are assumptions you enter — current rates vary by lender and product. See Bank of England for the official Bank Rate. Your actual payment depends on the product and fees.
How it works
- Enter your property price, deposit, interest rate and term.
- The calculator works out your loan amount (price − deposit) and LTV.
- It shows your monthly payment, total interest and total repaid over the term.
- For a repayment mortgage, a yearly breakdown shows how the balance falls.
Example calculation
For a £300,000 property with a £60,000 deposit (loan £240,000) at 5% over 25 years:
- Monthly payment (repayment): ≈ £1,403
- Loan-to-value: 80%
- Total repaid: ≈ £420,905
- Total interest: ≈ £180,905
Example assumes a fixed 5% rate for the whole term with no fees. Most UK mortgages fix for 2–5 years, then move to the lender's standard variable rate — your actual cost will differ.
Methodology & formula
For a repayment mortgage, the monthly payment uses the standard annuity formula:
M = P × r(1 + r)n / [ (1 + r)n − 1 ]
- P = loan amount (property price − deposit)
- r = monthly interest rate = annual rate ÷ 12
- n = number of monthly payments = term × 12
Total interest = (monthly payment × n) − P. For an interest-only mortgage, the monthly payment is simply P × r (interest only), and the loan is repaid separately at the end. LTV = loan ÷ property price.
Assumptions: constant interest rate for the whole term, no arrangement or other fees, no overpayments, monthly payments. Real rates move — a rate change can substantially change your payment.
UK-specific information
- Repayment vs interest-only: Most UK mortgages are repayment, so the loan is cleared by the end of the term. Interest-only is common for buy-to-let and requires a separate repayment vehicle.
- Fixed vs variable: UK mortgages typically fix for 2, 3 or 5 years, then revert to the lender's Standard Variable Rate (SVR). Tracker mortgages follow the Bank of England Bank Rate.
- LTV matters: A lower loan-to-value (bigger deposit) usually unlocks lower interest rates. Products are commonly banded at 60%, 75%, 80%, 85% and 90% LTV.
- Stamp Duty: buying a home in England or Northern Ireland may mean paying Stamp Duty Land Tax on the purchase price — separate from the mortgage. GOV.UK · 2026/27
Bank Rate and lender rates change frequently — this calculator uses the rate you enter.
Frequently asked questions
How much can I borrow for a UK mortgage?
What is a good deposit to save?
Repayment or interest-only — which should I choose?
Does the calculator include fees?
What happens when my fixed rate ends?
Can I make overpayments?
What would you like to calculate next?
How Much Can I Borrow?
Estimate your mortgage borrowing capacity based on income, deposit and existing debts.
Open →Mortgage Overpayment Calculator
See how much interest you could save and how many years you could cut off your term.
Open →Stamp Duty Calculator
Work out how much Stamp Duty you'll pay on your property purchase.
Open →Sources
- Bank of England — official Bank Rate and mortgage market data: bankofengland.co.uk
- MoneyHelper — mortgages and buying a home: moneyhelper.org.uk
Casvia provides educational calculators and general information. It does not provide personal financial, tax or investment advice. Interest rates and products change — always check the latest official guidance.