UK Mortgage Calculator
Calculate monthly mortgage repayments, total interest payable, and see a full year-by-year amortisation schedule. Enter the property price, deposit, interest rate and term — plus an optional income check to see how much you can borrow.
Monthly Payment (P&I)
£1,500.75
25-year term
Total Interest
£180,224
Over full term
Total Cost
£480,224
Deposit + payments
Loan-to-Value
90.0%
Borrowing £270,000
| Year | Interest Paid | Principal Paid | Balance |
|---|---|---|---|
| 1 | £12,028 | £5,981 | £264,019 |
| 2 | £11,753 | £6,256 | £257,763 |
| 3 | £11,465 | £6,544 | £251,219 |
| 4 | £11,165 | £6,844 | £244,375 |
| 5 | £10,850 | £7,159 | £237,216 |
| 6 | £10,522 | £7,487 | £229,729 |
| 7 | £10,178 | £7,831 | £221,898 |
| 8 | £9,818 | £8,191 | £213,706 |
| 9 | £9,442 | £8,567 | £205,139 |
| 10 | £9,048 | £8,961 | £196,178 |
| 11 | £8,636 | £9,373 | £186,805 |
| 12 | £8,206 | £9,803 | £177,002 |
| 13 | £7,755 | £10,254 | £166,748 |
| 14 | £7,284 | £10,725 | £156,024 |
| 15 | £6,792 | £11,217 | £144,806 |
| 16 | £6,276 | £11,733 | £133,073 |
| 17 | £5,737 | £12,272 | £120,802 |
| 18 | £5,173 | £12,835 | £107,966 |
| 19 | £4,584 | £13,425 | £94,541 |
| 20 | £3,967 | £14,042 | £80,499 |
| 21 | £3,322 | £14,687 | £65,812 |
| 22 | £2,647 | £15,362 | £50,451 |
| 23 | £1,942 | £16,067 | £34,383 |
| 24 | £1,203 | £16,806 | £17,578 |
| 25 | £431 | £17,578 | £0 |
Don’t forget Stamp Duty
Stamp Duty Land Tax can add thousands to your purchase cost.
Understanding your mortgage
Principal & Interest split
Each monthly payment is split between interest (the cost of borrowing) and principal (repaying the loan amount). Over time, the proportion shifts — early years are interest-heavy, later years principal-heavy. This is called amortisation.
Loan-to-Value (LTV) ratio
Your LTV is the loan amount divided by the property value, expressed as a percentage. A 90% LTV means a 10% deposit; a 60% LTV means a 40% deposit. Lower LTV ratios typically qualify for lower interest rates because the lender takes on less risk.
Term length impact
A longer mortgage term (30+ years) reduces your monthly payment but increases total interest payable over the life of the loan. A shorter term (15–20 years) means higher monthly payments but much less total interest. Many borrowers choose 25 years as a middle ground.
Overpayment strategy
Most UK lenders allow you to overpay up to 10% of the outstanding balance each year without penalty. Even small monthly overpayments can significantly reduce your total interest cost and shorten your mortgage term.
Frequently asked questions
How are monthly mortgage payments calculated?
Monthly mortgage payments are calculated using the loan amount, interest rate, and term. Each payment covers part of the interest due and part of the principal (the amount borrowed). Early in the term, a larger share goes to interest; over time, more goes to paying down the principal — this is called amortisation.
How much deposit do I need for a UK mortgage?
Most UK lenders require a minimum deposit of 5–10% of the property price. A 10% deposit (90% LTV) is the most common starting point, but a 20%+ deposit (80% LTV or lower) unlocks better interest rates. First-time buyer schemes like 95% mortgages (5% deposit) are available through the government-backed guarantee scheme.
What is the difference between fixed and variable rate mortgages?
A fixed-rate mortgage locks your interest rate for a set period (typically 2, 3, or 5 years), giving predictable monthly payments regardless of Bank of England base rate changes. A variable-rate mortgage (standard variable rate, tracker, or discounted rate) can go up or down with base rate movements — offering lower initial rates but less payment certainty.