Welcome to our free UK Mortgage Calculator. Instantly estimate your monthly repayments, total interest, and overall cost of a residential mortgage in the United Kingdom. This tool is designed for first-time buyers, home movers, and remortgagers who want quick, accurate figures without any registration.
How to Use This UK Mortgage Calculator
- Enter the property price or loan amount.
- Add your deposit (or leave blank if you already know the loan size).
- Choose the mortgage term in years (usually 25 or 30 years).
- Enter the current interest rate (check latest fixed or variable rates).
- Click Calculate to see monthly repayment, total interest, and total amount payable.
Mortgage Calculation Formula
Our calculator uses the standard amortisation formula used by UK lenders:
Monthly Payment (M) = P × [r(1+r)n] ÷ [(1+r)n − 1]
- P = Loan amount (property price − deposit)
- r = Monthly interest rate (annual rate ÷ 12 ÷ 100)
- n = Total number of monthly payments (years × 12)
This is the same formula used by most high-street banks and building societies in the UK.
Worked Example – UK First-Time Buyer
Imagine you are buying a £320,000 house in Manchester with a £40,000 deposit. You take a 25-year fixed-rate mortgage at 4.5% interest.
- Loan amount: £280,000
- Monthly repayment: approximately £1,556
- Total interest over 25 years: around £186,800
- Total amount payable: about £466,800
Figures are estimates only. Actual rates and fees vary between lenders. Always check the latest offers from banks such as Nationwide, Halifax, or HSBC, or use a regulated mortgage broker.
Important Factors That Affect Your UK Mortgage
- Loan-to-Value (LTV) – Lower deposit usually means higher interest rate.
- Credit score – Better score = better rates.
- Product fees – Some mortgages have arrangement fees of £999–£1,999.
- Stamp Duty Land Tax (SDLT) – First-time buyers may get relief (check current thresholds on the official GOV.UK Stamp Duty page).
- Stress testing – Lenders check if you can afford higher rates.
Fixed vs Variable Rate Mortgages
Most UK buyers start with a 2-year or 5-year fixed rate. After the fixed period ends, the loan usually moves to the lender’s Standard Variable Rate (SVR), which is often higher. You can use this calculator to compare different scenarios by simply changing the interest rate.
For more detailed affordability checks, you can also try our Percentage Calculator to work out deposit percentages and our Tip Calculator for everyday budgeting.
Frequently Asked Questions
How accurate is this mortgage calculator?
It uses the standard UK amortisation formula and gives a very close estimate. However, it does not include product fees, valuation fees, or early repayment charges. For exact figures always get a Decision in Principle from a lender.
What is a good deposit in the UK right now?
A 10–15% deposit is common for first-time buyers. A larger deposit (20%+) usually unlocks better interest rates and avoids higher LTV products.
Can I use this calculator for buy-to-let mortgages?
Yes, but buy-to-let mortgages often have different criteria (stress rates, higher deposits, and interest-only options). The repayment figures will still be useful for comparison.
Where can I check the latest UK mortgage rates?
You can compare current rates on the MoneySavingExpert mortgage section or the official MoneyHelper mortgage tools (government-backed).
Disclaimer: This calculator is for general guidance only and does not constitute financial advice. Mortgage rules, rates, and tax thresholds change regularly. Always speak to a qualified mortgage adviser or check the latest information on GOV.UK before making any decision. See our full Disclaimer page.
Need more tools? Try our Scientific Calculator or Percentage Calculator.