UK Mortgage — Complete Guide & Calculator
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Monthly repayment
£1,417.37
per month
Loan amount
£255,000.00
LTV: 85.0%
Total to repay
£425,211.85
over 25 years
Total interest
£170,211.85
40.0% of repayments
📊 Year-by-year breakdown (first 5 years)
| Year | Principal paid | Interest paid | Remaining balance |
|---|---|---|---|
| 1 | £5,649.04 | £11,359.43 | £249,350.96 |
| 2 | £5,908.56 | £11,099.92 | £243,442.40 |
| 3 | £6,179.99 | £10,828.48 | £237,262.41 |
| 4 | £6,463.90 | £10,544.57 | £230,798.51 |
| 5 | £6,760.85 | £10,247.62 | £224,037.65 |
🔒Calculated in your browser. For estimation only — speak to a mortgage broker for actual quotes.
How a UK mortgage repayment is calculated
Almost every UK mortgage is a repayment mortgage, which spreads the loan out so you owe nothing at the end of the term. The formula underneath is the same one this calculator runs:
M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)
M is the monthly payment, P the amount you borrow (price minus deposit),r the monthly rate (annual rate ÷ 12), and n the number of months.
So a £300,000 home with a £45,000 deposit means you borrow £255,000. At 4.5% over 25 years that's about £1,417 a month. Pay it all the way through and you'll hand over roughly £425,000, which means around £170,000 of it was interest. That interest is the real cost of borrowing.
What sets your monthly payment
Four things, really: your deposit, the interest rate, the length of the loan, and whether it's a repayment or interest-only mortgage.
Your deposit is the cash you put down, and LTV — loan-to-value — is what's left, shown as a percentage of the price. Put down £30,000 on a £300,000 home and you're borrowing at 90% LTV. The bigger the deposit, the lower the LTV, and the cheaper the rate a lender will offer.
The interest rate is what you pay on the money you still owe. Half a percent sounds like nothing, but on a £255,000 loan, 4.5% costs about £21,000 more in interest than 4.0% over 25 years.
The term is how long you spread it over. 25 years is the default, though 30 and 35-year terms have crept in as prices have risen. Longer term, lower monthly payment — but more interest overall.
Repayment vs interest-only. A repayment mortgage clears the balance by the end and is what nearly everyone has. Interest-only just covers the interest each month, leaving the capital to be repaid as a lump sum at the end — lenders now want to see a credible plan for that before they'll offer one.
Monthly repayments at common UK prices
These assume a 15% deposit, 4.5% interest and a 25-year term. Your own rate will shift with your deposit and credit history, so treat these as a starting point.
| Property price | Deposit (15%) | Loan (85%) | Monthly repayment | Total interest |
|---|---|---|---|---|
| £150,000 | £22,500 | £127,500 | £709 | £85,106 |
| £200,000 | £30,000 | £170,000 | £945 | £113,475 |
| £250,000 | £37,500 | £212,500 | £1,181 | £141,843 |
| £300,000 | £45,000 | £255,000 | £1,417 | £170,212 |
| £350,000 | £52,500 | £297,500 | £1,654 | £198,580 |
| £400,000 | £60,000 | £340,000 | £1,890 | £226,949 |
| £450,000 | £67,500 | £382,500 | £2,126 | £255,318 |
| £500,000 | £75,000 | £425,000 | £2,362 | £283,686 |
| £550,000 | £82,500 | £467,500 | £2,599 | £312,055 |
| £600,000 | £90,000 | £510,000 | £2,835 | £340,424 |
| £700,000 | £105,000 | £595,000 | £3,307 | £397,161 |
| £800,000 | £120,000 | £680,000 | £3,780 | £453,898 |
| £900,000 | £135,000 | £765,000 | £4,252 | £510,636 |
| £1,000,000 | £150,000 | £850,000 | £4,725 | £567,373 |
Fixed-rate vs variable-rate
A fixed-rate mortgage locks your rate for a set stretch — usually 2, 3, 5 or 10 years — so your payments stay the same whatever the Bank of England does. That predictability is why most people pick one. The trade-offs: most fixed deals charge an early repayment penalty if you leave mid-term, and when the fix ends you'll drop onto the lender's standard variable rate unless you remortgage.
A tracker mortgage follows the Bank of England base rate plus a set margin, so your payment rises and falls with it. Cheaper when rates are falling, less comfortable when they're climbing.
The standard variable rate (SVR) is what you land on once a fixed or tracker deal ends, and it's usually noticeably higher than the deal you came from. Most people remortgage rather than sit on it.
How your deposit changes the rate
Lenders price mortgages in bands. The more you put down, the less risk they take on, and the better the rate.
| Deposit | LTV | What it means |
|---|---|---|
| 5% | 95% LTV | The minimum, often via the government Mortgage Guarantee Scheme. Highest rates. |
| 10% | 90% LTV | A common first-time-buyer starting point, with noticeably better rates than 95%. |
| 15% | 85% LTV | The middle ground we used in the tables above. |
| 25% | 75% LTV | Rates improve a lot here, which is why it's a popular remortgage target. |
| 40% | 60% LTV | The best rates on offer. Lenders reserve their lowest pricing for this tier. |
How much you can borrow
Most UK lenders will offer between 4 and 4.5× your annual gross income, and some stretch to 5 or 5.5× for higher earners. On top of that they run an affordability check on your outgoings, debts and dependants, so the income multiple is only half the picture.
As a rough guide, a £40,000 household income usually supports a mortgage of around £160,000 to £180,000. Add your deposit on top and that's your ceiling.
The mortgage isn't the only bill
Buying a UK home also means Stamp Duty (SDLT), which can run into the thousands on its own, plus solicitor fees, surveys and moving costs. In Scotland it's LBTT instead. Plenty of first-time buyers budget for the mortgage and get caught out by the tax on top.
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Frequently Asked Questions
How much is the monthly repayment on a UK mortgage?
A £300,000 home with a 15% deposit (£45,000) at 4.5% over 25 years costs about £1,417/month. The loan is £255,000 and total interest over the full term is roughly £170,000. Use the calculator above to plug in your own price, deposit and rate.
What deposit do I need for a UK mortgage?
The minimum is usually 5% (95% LTV), often available through the government Mortgage Guarantee Scheme. 10% (90% LTV) is the common first-time-buyer starting point, and 15% (85% LTV) unlocks noticeably better rates. The best rates come at 40% deposit (60% LTV).
What is LTV on a mortgage?
LTV (loan-to-value) is the loan amount as a percentage of the property price. A 10% deposit means 90% LTV. Lower LTV means lower risk for the lender, so you get a better interest rate.
Should I choose a fixed-rate or variable-rate mortgage?
Fixed-rate locks your rate for 2, 3, 5 or 10 years, giving predictable payments but usually an early repayment charge. Tracker mortgages follow the Bank of England base rate plus a margin. Fixed is best if you value certainty; tracker can be cheaper if rates fall.
How much can I borrow for a UK mortgage?
Most lenders offer 4–4.5× your annual gross income, sometimes up to 5–5.5× for higher earners. They also run an affordability check on your outgoings. A £40,000 income typically supports a £160,000–£180,000 loan.