Your monthly mortgage payment is determined by four variables: the loan amount (property price minus deposit), the interest rate, the mortgage term, and the repayment type. All four work together — changing any one of them can move your monthly payment by hundreds of pounds.
All figures in this guide assume capital and interest repayment mortgages with monthly compounding — the standard for almost all residential mortgages in the UK.
The table below shows estimated monthly mortgage payments at a 4.5% interest rate with a 10% deposit across common property prices and mortgage terms. These figures are for illustration — use the Mortgage Calculator or Mortgage Affordability Calculator for your specific figures.
| Property price | Mortgage (90%) | 20-yr payment | 25-yr payment | 30-yr payment |
|---|---|---|---|---|
| £150,000 | £135,000 | £854 | £750 | £684 |
| £200,000 | £180,000 | £1,139 | £1,000 | £912 |
| £250,000 | £225,000 | £1,423 | £1,251 | £1,140 |
| £300,000 | £270,000 | £1,708 | £1,501 | £1,368 |
| £400,000 | £360,000 | £2,277 | £2,002 | £1,824 |
| £500,000 | £450,000 | £2,846 | £2,502 | £2,281 |
| £750,000 | £675,000 | £4,270 | £3,753 | £3,421 |
Based on 4.5% annual interest rate, 10% deposit, capital and interest repayment. Actual payments depend on your lender, rate and circumstances.
A longer mortgage term reduces your monthly payment but substantially increases total interest paid. On a £270,000 mortgage at 4.5%:
The difference between a 20-year and 30-year term at this level: £340/month cheaper, but £82,600 more in total interest. Extending the term is a common strategy to pass a lender's affordability test or reduce monthly pressure — but the long-term cost is significant.
Most UK residential mortgages are capital and interest (repayment) mortgages — each monthly payment covers the interest due plus a portion of the original loan, so the debt is fully cleared by the end of the term. Interest-only mortgages have lower monthly payments but leave the full original loan balance outstanding at the end of the term, requiring a separate repayment plan.
| Mortgage type | Loan | Rate | Term | Monthly payment | Balance at end |
|---|---|---|---|---|---|
| Capital repayment | £250,000 | 4.5% | 25 years | £1,389 | £0 |
| Interest-only | £250,000 | 4.5% | 25 years | £938 | £250,000 |
Interest-only monthly payment = loan × annual rate ÷ 12. The full £250,000 loan balance remains due at the end of the term — no capital has been repaid.
Interest-only saves £451/month compared to capital repayment on the same mortgage. However, because the loan balance never reduces, interest accumulates on the full £250,000 for the entire 25 years. Over the term at 4.5%, interest-only borrowers pay approximately £281,400 in total interest versus approximately £166,700 for capital repayment — around £115,000 more.
Interest-only restrictions: Residential interest-only mortgages require a credible approved repayment vehicle — such as an investment portfolio, pension, ISA or planned property sale. They are harder to obtain than capital repayment mortgages and are primarily used in buy-to-let. Almost all first-time buyer and standard residential mortgages are capital repayment. Confirm with your broker which products you qualify for.
Interest rates are the most volatile input in a mortgage payment. The table below shows how monthly payments change on a £300,000 mortgage over 25 years at different rates.
| Annual rate | Monthly payment | vs 4.5% baseline | Total interest |
|---|---|---|---|
| 3.5% | £1,502 | −£165/month | £150,600 |
| 4.0% | £1,583 | −£84/month | £174,900 |
| 4.5% (current) | £1,667 | — | £200,100 |
| 5.0% | £1,754 | +£87/month | £226,200 |
| 5.5% | £1,842 | +£175/month | £252,600 |
£300,000 capital and interest mortgage, 25-year term. Rates are for illustration — your actual offer depends on your LTV, income and credit profile.
Rate impact rule of thumb: On a £200,000 mortgage over 25 years, each 0.25% rise in your interest rate adds approximately £27/month to your payment. On a £400,000 mortgage, the same 0.25% rise adds approximately £54/month.
Your loan-to-value ratio (LTV) is your mortgage as a percentage of the property value. A larger deposit means a lower LTV, which reduces lender risk — and lenders typically pass this on as a lower interest rate. The combined effect of borrowing less money at a lower rate can make a substantial difference to your monthly payment even when the property price is identical.
| Deposit | LTV | Mortgage (£250k property) | Illustrative rate | Monthly payment (25yr) |
|---|---|---|---|---|
| 5% — £12,500 | 95% | £237,500 | 5.5% | £1,458 |
| 10% — £25,000 | 90% | £225,000 | 4.8% | £1,289 |
| 15% — £37,500 | 85% | £212,500 | 4.5% | £1,181 |
| 20% — £50,000 | 80% | £200,000 | 4.3% | £1,089 |
| 25% — £62,500 | 75% | £187,500 | 4.1% | £1,000 |
| 40% — £100,000 | 60% | £150,000 | 3.9% | £783 |
Illustrative rates only — actual offers depend on lender, product, credit profile and market conditions. See UK Mortgage Rates 2026 for current LTV-banded rate ranges.
Going from a 5% to a 25% deposit on the same £250,000 property reduces the monthly payment by £458/month (£5,496/year) — even though the mortgage is only £50,000 smaller. The rate improvement compounds the savings over the full term. The most significant rate step-changes typically occur at the 90% and 75% LTV thresholds.
Calculate your LTV: The Mortgage Affordability Calculator shows how changing your deposit affects your maximum borrowing and monthly payment. A broker can confirm which LTV band you fall into and what rates are currently available at each tier.
Monthly costs vary dramatically by region, driven almost entirely by house prices. The table below uses approximate regional average house prices in 2026, a 20% deposit and a 25-year term at 4.5%.
| Region | Avg house price | Mortgage (80% LTV) | Est. monthly payment |
|---|---|---|---|
| London | £520,000 | £416,000 | £2,312 |
| South East | £380,000 | £304,000 | £1,689 |
| East of England | £325,000 | £260,000 | £1,445 |
| South West | £310,000 | £248,000 | £1,378 |
| UK Average | £285,000 | £228,000 | £1,267 |
| West Midlands | £245,000 | £196,000 | £1,090 |
| East Midlands | £240,000 | £192,000 | £1,067 |
| North West | £225,000 | £180,000 | £1,000 |
| Yorkshire & Humber | £215,000 | £172,000 | £956 |
| Wales | £215,000 | £172,000 | £956 |
| Scotland | £195,000 | £156,000 | £867 |
| North East | £165,000 | £132,000 | £734 |
Regional averages based on approximate 2026 house prices. Payments assume 20% deposit, 25-year term, 4.5% rate. Actual prices vary significantly within regions.
The gap between London (£2,312/month) and the North East (£734/month) is £1,578/month on an average property — illustrating why affordability pressures are so regionally concentrated. A 10% deposit rather than 20% would increase all payments by approximately 12.5%.
The mortgage type you choose affects how stable your monthly payment is over time. In 2026, most borrowers are choosing between two main options.
Your interest rate — and therefore your monthly payment — is locked for the agreed term, typically 2 or 5 years. At the end of the fixed term, you revert to the lender's Standard Variable Rate (SVR) unless you remortgage. SVRs are typically 1–3% higher than the best fixed rates.
Your rate is set as a margin above the Bank of England base rate (e.g. base rate + 1.5%). Your monthly payment changes whenever the base rate changes.
2026 context: The Bank of England base rate peaked at 5.25% in 2023 and has been gradually declining. Most analysts expect further gradual falls into 2026–2027. Borrowers considering tracker mortgages should stress-test their budget at the current rate and higher — not just at the rate if rates fall.
For most homeowners, monthly costs change most significantly not when the base rate moves, but when a fixed deal expires and they remortgage — or fail to. Understanding what drives these changes lets you plan well in advance and avoid the most expensive outcome.
When a fixed or tracker deal expires, you automatically revert to the lender's Standard Variable Rate unless you actively remortgage. SVRs in 2026 are typically 6.5–8% — often 2–3 percentage points higher than the best available fixed deals. On a £250,000 outstanding balance, reverting to a 7.5% SVR instead of securing a new 4.5% fix adds approximately £430–£480/month. Always start remortgage conversations 3–6 months before your deal expires.
On a capital repayment mortgage, each payment reduces your outstanding balance. After 5 years on a typical 25-year deal, you will have repaid roughly 10–15% of the original loan — meaning you borrow less at remortgage. This partially offsets a higher rate, but rarely fully compensates for moving from a sub-3% fix to today's 4–5% deals.
Some borrowers use remortgage to shorten their remaining term — for example, from 20 to 17 years — to reduce total interest paid. This can increase monthly payments even at a similar rate, but substantially reduces the total cost of the mortgage.
Original mortgage: £300,000 at 2.1% fixed in 2021, 25-year term. Monthly payment: £1,285/month.
After 5 years: outstanding balance approximately £252,000. 20 years remaining.
New 5-year fix at 4.5% over 20 years: £1,594/month — an increase of £309/month.
Revert to SVR at 7.5% over 20 years: £2,030/month — an increase of £745/month.
Remortgaging to a new fix saves approximately £436/month compared to reverting to SVR — over £5,200/year.
Lenders also run an affordability stress test at remortgage — checking you can still afford the mortgage at a higher rate, even when you are not borrowing more. For current stress rates and how lender affordability checks work in 2026, see our Mortgage Stress Test guide.
Emma is buying a £195,000 flat with a 5% deposit (£9,750), giving a mortgage of £185,250. She secures a 2-year fixed rate at 4.5% over a 25-year term.
Monthly payment: £1,030
Annual mortgage cost: £12,360
Total interest over 25 years (if rate unchanged): approximately £123,600
Lender's stress test at 7.5%: £1,371/month — Emma confirms she could manage this before her application is approved.
At 90%+ LTV, Emma's rate is higher than a buyer with a larger deposit. Saving an additional £5,000 deposit would take her to approximately 97.5% LTV — but reaching 90% LTV (£19,500 deposit) would unlock noticeably better rates and reduce her monthly payment by around £40–£60.
Mark and Sarah are selling their current flat (equity: £78,000) and buying a £340,000 home with a 20% deposit (£68,000). Their mortgage is £272,000 over 22 years at 4.25% fixed.
Monthly payment: £1,587
Annual mortgage cost: £19,044
Their 80% LTV gives access to competitive rates. The 22-year term is slightly shorter than the standard 25 years — a deliberate choice to clear the mortgage before retirement.
If rates fall to 3.75% at remortgage in 2 years: monthly payment would reduce to approximately £1,530, saving £57/month and roughly £1,368/year.
The Hendersons own a £380,000 home with £185,000 outstanding on their mortgage. Their 2-year fixed deal is ending. They remortgage over 15 years at 4.3%.
Monthly payment: £1,396
Annual mortgage cost: £16,752
At 49% LTV, the Hendersons access the best rate tiers. The 15-year term (rather than extending back to 25 years) means they clear the mortgage at age 67 — before state pension age. Their total remaining interest is approximately £66,300. If they extended to 25 years instead: payment would fall to ~£1,030/month but total interest would rise to approximately £124,000 — an extra £57,700 in interest for £366/month of payment relief.
Enter your income, deposit, and commitments to see exactly how much you can borrow and what your monthly payment would be.
Use the Mortgage Affordability Calculator →Disclaimer: All figures in this guide are for illustrative purposes only. Actual monthly mortgage payments depend on the interest rate offered by your lender, your loan-to-value ratio, your credit history, the specific product and any fees added to the loan. Interest rates change frequently — figures represent typical ranges as of mid-2026. This guide does not constitute financial advice. Speak to a qualified mortgage broker or financial adviser before making any borrowing decision.