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How Much Will a £X Mortgage Cost Per Month? UK Repayment Examples for 2026
If you’re working out what a mortgage will actually cost you each month, you’ve probably tried a calculator and walked away with a number but no real context. This guide shows you what mortgages of different sizes genuinely cost in 2026, across the most common loan amounts and terms, with worked examples so you can see how the numbers move when you change one variable.
All figures use a 4.5% interest rate as a representative example based on current UK market conditions in 2026. Your actual rate will depend on your deposit size, loan-to-value ratio, credit profile and lender, so treat these as planning numbers, not quotes.
In this guide
- How mortgage repayments are calculated
- Monthly cost by mortgage size
- Worked examples: £100k to £500k mortgages
- How interest rate changes affect your monthly payment
- Repayment vs interest-only: what’s the difference?
- What term length should you choose?
- How to get a better rate
- Frequently asked questions
How mortgage repayments are calculated
Your monthly mortgage payment depends on three things: the loan amount, the interest rate, and the term (how many years you’re paying it back over).
On a standard repayment mortgage, every monthly payment chips away at both the interest and the loan balance itself. Early on, most of your payment goes on interest. Later in the term, more of it goes on capital. By the end, the loan is fully paid off and you own your property outright.
The maths isn’t linear. Doubling your loan doesn’t double your interest cost over time, and shaving five years off your term increases your monthly payment by less than you’d expect. The tables below show how this plays out at common loan sizes.
Quick estimate: Try our monthly mortgage payment calculator for an instant figure based on your numbers.
Monthly cost by mortgage size
Here’s what monthly repayments look like across a range of common UK mortgage amounts, all at 4.5% interest over standard terms.
| Loan amount | 20-year term | 25-year term | 30-year term |
|---|---|---|---|
| £100,000 | £633 | £556 | £507 |
| £150,000 | £949 | £834 | £760 |
| £200,000 | £1,265 | £1,112 | £1,013 |
| £250,000 | £1,581 | £1,390 | £1,267 |
| £300,000 | £1,898 | £1,668 | £1,520 |
| £350,000 | £2,214 | £1,946 | £1,773 |
| £400,000 | £2,530 | £2,224 | £2,027 |
| £450,000 | £2,847 | £2,502 | £2,280 |
| £500,000 | £3,163 | £2,780 | £2,533 |
Worth knowing: the 25-year term is still the UK default, but 30 and 35-year terms are increasingly common, particularly for first-time buyers stretching affordability and for buyers in higher-priced areas like the Thames Valley.
Worked examples
£100,000 mortgage
A £100,000 mortgage is at the smaller end of the modern UK market. It’s typical for buyers in lower-cost regions, or for anyone with a substantial deposit on a mid-range property.
- 20 years: £633 per month, total interest £51,840
- 25 years: £556 per month, total interest £66,640
- 30 years: £507 per month, total interest £82,420
The temptation to take a 30-year term is real (you save £126 per month) but you pay an extra £30,580 in interest over the life of the loan.
£200,000 mortgage
This is roughly the UK average mortgage size. At a 4.5% rate it works out:
- 20 years: £1,265 per month, total interest £103,680
- 25 years: £1,112 per month, total interest £133,280
- 30 years: £1,013 per month, total interest £164,840
For most buyers, the 25-year term hits the sweet spot: manageable monthly payments without an excessive interest bill.
£300,000 mortgage
A £300,000 mortgage is now common for buyers in southern England, particularly across Berkshire, Buckinghamshire and the wider Thames Valley.
- 20 years: £1,898 per month, total interest £155,520
- 25 years: £1,668 per month, total interest £200,400
- 30 years: £1,520 per month, total interest £247,200
At this loan size, the term decision matters more. You’re looking at nearly £92,000 difference in total interest between 20 and 30 years.
£400,000 mortgage
A £400,000 mortgage is typical for family home purchases in places like Marlow, Maidenhead, Henley and Beaconsfield.
- 20 years: £2,530 per month, total interest £207,200
- 25 years: £2,224 per month, total interest £267,200
- 30 years: £2,027 per month, total interest £329,720
You’ll typically need a household income of £80,000 to £100,000 to qualify for a £400,000 mortgage, depending on lender and circumstances.
£500,000 mortgage
At £500,000 you’re approaching the threshold where some lenders treat the application as a large mortgage, and where specialist underwriting can unlock better rates.
- 20 years: £3,163 per month, total interest £259,120
- 25 years: £2,780 per month, total interest £334,000
- 30 years: £2,533 per month, total interest £411,880
If you’re borrowing this much, talking to a broker who handles large mortgage loans is worth the call. High-street lenders often aren’t the most competitive at this level.
How interest rate changes affect your monthly payment
A 1% change in your interest rate has a bigger impact than most people realise. Here’s what a £250,000 mortgage over 25 years costs at different rates:
| Interest rate | Monthly payment | Total cost over 25 years |
|---|---|---|
| 3.5% | £1,252 | £375,600 |
| 4.0% | £1,319 | £395,700 |
| 4.5% | £1,390 | £417,000 |
| 5.0% | £1,462 | £438,600 |
| 5.5% | £1,535 | £460,500 |
| 6.0% | £1,611 | £483,300 |
The gap between the best and worst rate available to you can easily be £150 to £300 per month on a typical mortgage. Over 25 years, that’s £45,000 to £90,000. This is the single biggest reason to use a whole-of-market broker rather than going direct to one lender.
Repayment vs interest-only
The figures above are all for repayment mortgages, where you pay back capital and interest each month and own the property outright at the end of the term.
With an interest-only mortgage you only pay the interest each month. This is significantly cheaper monthly, but you still owe the full loan at the end of the term and need a separate plan to repay it (typically investments, downsizing, or a pension lump sum).
A £300,000 interest-only mortgage at 4.5% costs £1,125 per month, versus £1,668 for a repayment mortgage on the same terms. That’s a £543 monthly saving, but you still owe £300,000 at the end.
Interest-only is mainly used for:
- Buy-to-let mortgages (almost always interest-only)
- High-net-worth borrowers with clear repayment vehicles
- Specialist circumstances where flexibility matters more than long-term cost
For most residential buyers, repayment is the right answer.
What term length should you choose?
There’s no single right answer. It depends on your age, income trajectory, and how comfortable you are with monthly payments versus total interest cost.
Some practical principles:
- Younger buyers can usually afford longer terms (30 to 35 years) without lender concerns about retirement age affordability
- Buyers in their 40s and 50s may face term length restrictions if the mortgage extends past their expected retirement age
- High earners often choose shorter terms (15 to 20 years) to clear the loan faster and reduce lifetime interest cost
- Buyers stretching affordability may need a longer term simply to bring monthly payments down to a level the lender will approve
You can also overpay most mortgages by 10% per year without penalty. That means you can take a longer term for safety and overpay when income allows, getting the best of both worlds.
How to get a better rate
The headline rate matters more than almost any other variable in this calculation. A few practical levers:
- Increase your deposit if you can. Loan-to-value bands at 60%, 75%, 80% and 85% all have meaningfully different rates. Pushing your deposit from 10% to 15% can move you into a better band.
- Check your credit file before applying. Errors and old defaults are common and easy to fix, but only if you spot them in time.
- Don’t accept your existing lender’s renewal offer without comparing. It is almost never the best rate on the market.
- Use a whole-of-market broker. High-street comparison sites only cover a fraction of available products. A broker has access to lender exclusives and specialist deals you won’t see elsewhere.
Want to know what rate you’d actually qualify for? Book a free 15-minute consultation and we’ll give you a realistic picture based on 90+ lenders.
A note on rate changes mid-mortgage
The figures in this guide assume a single interest rate for the full term. In reality, most UK mortgages are fixed for two or five years, then revert to a variable rate (typically much higher). Most borrowers remortgage to a new fixed deal at that point.
This means your real total cost depends on what rates do in future and how well you manage your remortgage transitions. A good broker should be flagging your remortgage window 4 to 6 months before your fixed period ends, not waiting for you to call them.
Frequently asked questions
How much is a £200,000 mortgage per month in the UK? At a 4.5% interest rate over 25 years, a £200,000 repayment mortgage costs around £1,112 per month. Over 30 years it falls to about £1,013, and over 20 years it rises to roughly £1,265. Your actual rate will depend on your deposit, credit profile and the lender.
How much is a £300,000 mortgage per month? At 4.5% over 25 years, a £300,000 repayment mortgage costs approximately £1,668 per month. The same loan over 30 years works out at around £1,520, and over 20 years it rises to about £1,898.
How much is a £500,000 mortgage per month? At 4.5% over 25 years, a £500,000 repayment mortgage costs around £2,780 per month. Larger loans of this size are usually classed as large mortgages and may have access to specialist rates and underwriting. This matters particularly if your income includes bonuses, dividends or self-employment profits.
What’s the difference between interest-only and repayment mortgages? With a repayment mortgage you pay back both the loan and the interest each month, and you own the property outright at the end of the term. With an interest-only mortgage you only pay the interest each month, so monthly costs are much lower. However, you still owe the original loan amount at the end and need a separate plan to repay it.
Does a longer mortgage term mean cheaper monthly payments? Yes. Extending your mortgage term reduces your monthly payment, but you’ll pay significantly more interest over the life of the loan. A £250,000 mortgage at 4.5% over 30 years costs around £1,267 per month but £206,000 in total interest. The same loan over 20 years costs £1,581 per month but only £130,000 in interest, a difference of around £76,000.
How accurate are mortgage calculator estimates? Calculator estimates are a useful starting point but assume one fixed interest rate for the entire term. In reality, most UK mortgages are fixed for two or five years, then revert to a variable rate. Your real total cost will depend on what you remortgage to. A broker can model these scenarios properly.
Not sure which loan size or term works for your situation?
Book a free, no-obligation chat with one of our independent mortgage advisers. We’ll model the real numbers across multiple lenders so you know exactly where you stand before you make an offer.
Frequently asked questions
- How much is a £200,000 mortgage per month in the UK?
- At a 4.5% interest rate over 25 years, a £200,000 repayment mortgage costs around £1,112 per month. Over 30 years it falls to about £1,013, and over 20 years it rises to roughly £1,265. Your actual rate will depend on your deposit, credit profile and the lender.
- How much is a £300,000 mortgage per month?
- At 4.5% over 25 years, a £300,000 repayment mortgage costs approximately £1,668 per month. The same loan over 30 years works out at around £1,520, and over 20 years it rises to about £1,898.
- How much is a £500,000 mortgage per month?
- At 4.5% over 25 years, a £500,000 repayment mortgage costs around £2,780 per month. Larger loans of this size are usually classed as large mortgages and may have access to specialist rates and underwriting. This matters particularly if your income includes bonuses, dividends or self-employment profits.
- What's the difference between interest-only and repayment mortgages?
- With a repayment mortgage you pay back both the loan and the interest each month, and you own the property outright at the end of the term. With an interest-only mortgage you only pay the interest each month, so monthly costs are much lower. However, you still owe the original loan amount at the end and need a separate plan to repay it.
- Does a longer mortgage term mean cheaper monthly payments?
- Yes. Extending your mortgage term reduces your monthly payment, but you'll pay significantly more interest over the life of the loan. A £250,000 mortgage at 4.5% over 30 years costs around £1,267 per month but £206,000 in total interest. The same loan over 20 years costs £1,581 per month but only £130,000 in interest, a difference of around £76,000.
- How accurate are mortgage calculator estimates?
- Calculator estimates are a useful starting point but assume one fixed interest rate for the entire term. In reality, most UK mortgages are fixed for two or five years, then revert to a variable rate. Your real total cost will depend on what you remortgage to. A broker can model these scenarios properly.
Gaurav Shukla
CEO · CeMAP DipFA
Gaurav has over a decade of experience spanning top brokerages, fintech startups, and wealth management firms. He specialises in high-value mortgages for professionals and athletes, bringing a strategic, client-first approach to every case.
A CeMAP and DipFA qualified adviser, he founded Home Me Mortgages with a simple goal: to make expert mortgage advice genuinely accessible across Berkshire, Buckinghamshire, and London. An avid football fan, you will often find Gaurav at local grounds taking in a game at the weekend.