10.0% deposit · 90.0% LTV
Monthly mortgage payment: £1,501. Loan amount £270,000.
A £270,000 mortgage at 4.5% over 25 years works out at about £1,501 a month. Over the full term you'd pay £180,224 in interest — £451,223 in total.
Principal vs interest
If your rate rises
| Interest rate | Monthly payment | vs now |
|---|---|---|
| 4.5% (now) | £1,501 | — |
| 5.5% (+1) | £1,658 | +£157/mo |
| 6.5% (+2) | £1,823 | +£322/mo |
| 7.5% (+3) | £1,995 | +£495/mo |
What your monthly payment would become if you remortgaged onto a higher rate — e.g. when a fixed deal ends.
Balance over time
| Year | Interest | Principal | Balance |
| 1 | £12,028 | £5,981 | £264,019 |
| 6 | £10,522 | £7,487 | £229,729 |
| 11 | £8,636 | £9,373 | £186,805 |
| 16 | £6,276 | £11,733 | £133,073 |
| 21 | £3,322 | £14,687 | £65,812 |
| 25 | £431 | £17,578 | £0 |
How much can I borrow?
| Estimated borrowing (4–4.5× income) | £180,000 – £202,500 |
| Max property price with your £30,000 deposit | £232,500 |
A rough guide — most UK lenders cap borrowing at around 4.5× income. Your actual limit also depends on your outgoings, credit history and the lender's affordability stress test.
Upfront buying costs
| Deposit | £30,000 |
| SDLT (stamp duty) | £5,000 |
| Mortgage arrangement fee | £999 |
| Legal / conveyancing fees | £1,500 |
| Survey | £500 |
| Removal / moving costs | £1,200 |
| Total cash needed | £39,199 |
Stamp duty is estimated from your property price for the buyer type above. Legal, survey and moving costs are editable estimates — your actual quotes will vary.
Frequently asked questions
How are monthly mortgage repayments calculated?
A repayment mortgage uses the loan amount, interest rate and term in a standard amortisation formula. Early on, most of each payment is interest; over time more goes towards the balance. This calculator assumes a constant interest rate for the whole term, so a real deal with a fixed period followed by a variable rate may differ.
How much can I borrow for a mortgage?
Most lenders cap borrowing at around 4 to 4.5 times your gross annual income, though affordability also depends on your outgoings, credit history and the stress-tested rate. Use your take-home pay to judge what monthly payment is comfortable, then check it against the lender’s income multiple.
What is loan-to-value (LTV)?
LTV is the loan as a percentage of the property value. A £180,000 loan on a £200,000 home is 90% LTV. Lower LTV (a bigger deposit) usually unlocks better interest rates, with the best deals typically at 60% LTV or below.
Should I choose a longer or shorter mortgage term?
A longer term lowers your monthly payment but increases the total interest you pay over the life of the loan. A shorter term costs more each month but far less overall. Overpaying when you can is a flexible middle ground — see the mortgage overpayment calculator.
What other costs are there when buying a home?
Beyond the deposit and monthly payments, budget for stamp duty, legal/conveyancing fees, a survey, mortgage arrangement fees, removals and buildings insurance. The buying-costs section of this calculator estimates the upfront cash you’ll need.
Related calculators & guides
Sources & guidance
Last reviewed June 2026 against official rates · How we calculate →
This is an illustrative estimate assuming a constant interest rate over the full term. Real mortgages may have fixed and variable periods, arrangement fees, and rates that change. Your home may be repossessed if you do not keep up repayments. This is not financial advice — obtain a personalised mortgage illustration from a lender or broker.
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