How to Calculate UK Mortgage Payments: Complete 2026 Guide

A £270,000 mortgage at 4.0% over 25 years costs £1,425 a month under the rates prevailing in mid-2026. The Bank of England base rate stands at 3.75% (held 18 June 2026, cut from 4.00% on 30 April 2026) and the average UK property price reached £270,000 in April 2026 (ONS, Private rent and house prices, published 17 June 2026). December 2025's mortgage price war produced 60% LTV 2-year fixes at 3.55% — the lowest published rates since September 2022 — and the April 2026 base-rate cut has compressed best-buys further.

This guide walks through the mortgage payment formula, shows worked examples at current rates, and explains how deposit size, term, and interest rate each move the monthly payment.

Quick summary

• Monthly payments depend on property price, deposit, interest rate, and loan term
• The formula uses compound interest applied to the outstanding balance
• Bank of England base rate: 3.75% (held 18 June 2026)
• Representative best rates (60% LTV): around 3.5% for 2-year fixes, 3.7% for 5-year fixes (anchored to December 2025 published rates with further compression after the April 2026 cut)
• Average UK house price: £270,000 (ONS, April 2026)

Understanding mortgage payment components

A monthly payment is determined by four factors.

1. Property price The total purchase price of the home. UK regional ONS averages (April 2026):

• England: £294,000
• Wales: £207,000
• Scotland: £190,000
• Northern Ireland: £185,000

2. Deposit The upfront cash, typically 5–20% of the property price. A larger deposit reduces the loan-to-value (LTV) ratio, which in turn unlocks better interest rates. On a £300,000 property, a 10% deposit means borrowing £270,000.

3. Interest rate The cost of borrowing, expressed as an annual percentage. As of December 2025 (the latest documented best-buy snapshot on this site), 2-year fixes at 60% LTV started at 3.55% (Santander) and 5-year fixes at 3.76%. The Bank of England cut the base rate from 4.00% to 3.75% on 30 April 2026 and held at 3.75% on 18 June 2026; fixed-rate pricing has tracked similarly downwards.

4. Mortgage term The years over which the loan is repaid, typically 25–35 in the UK. A longer term lowers the monthly payment but increases total interest.

The UK mortgage payment formula

UK repayment mortgages use the standard amortising-loan formula:

M = P × r(1+r)^n / ((1+r)^n − 1)

Where:

• M = monthly payment
• P = principal (amount borrowed = property price − deposit)
• r = monthly interest rate (annual rate ÷ 12 ÷ 100)
• n = total number of monthly payments (years × 12)

Worked example

Step 1: Calculate the principal

• Property price: £300,000
• Deposit (10%): £30,000
• Principal: £270,000

Step 2: Convert the annual rate to monthly

• Annual rate: 4.0%
• Monthly rate: 4.0 ÷ 12 ÷ 100 = 0.003333
• r = 0.003333

Step 3: Total number of payments

• Term: 25 years
• n = 25 × 12 = 300

Step 4: Apply the formula

• (1+r)^n ≈ 2.7136
• M = £270,000 × (0.003333 × 2.7136) / (2.7136 − 1)
• M = £270,000 × 0.005277
• M ≈ £1,425 a month

Calculate Your Mortgage Payments →

Real examples: UK mortgage payments at mid-2026 rates

The examples below use the best-buy 60% LTV rates documented at end-2025 (Santander 2-year fix at 3.55%) and a representative 4.0% rate that reflects typical 75–85% LTV pricing post the April 2026 base-rate cut.

Example 1: Average UK property (£300,000)

• Property price: £300,000
• Deposit (10%): £30,000
• Amount borrowed: £270,000
• Interest rate: 4.0% (representative 75% LTV 2-year fix, mid-2026)
• Term: 25 years

Monthly payment: £1,425 Total repayable: £427,500 Total interest: £157,500

Example 2: First-time buyer (£250,000)

• Property price: £250,000
• Deposit (5%): £12,500
• Amount borrowed: £237,500
• Interest rate: 4.7% (representative 95% LTV 2-year fix, mid-2026)
• Term: 30 years

Monthly payment: £1,232 Total repayable: £443,520 Total interest: £206,020

Example 3: Family home (£500,000)

• Property price: £500,000
• Deposit (15%): £75,000
• Amount borrowed: £425,000
• Interest rate: 3.85% (representative 85% LTV 5-year fix, mid-2026)
• Term: 25 years

Monthly payment: £2,209 Total repayable: £662,700 Total interest: £237,700

How deposit size affects payments

Deposit size moves both the monthly payment and the interest rate. The table uses a £300,000 property with mid-2026 representative rates by LTV band.

Deposit	Amount borrowed	Rate	Monthly payment	Difference
5% (£15k)	£285,000	4.7%	£1,617	Baseline
10% (£30k)	£270,000	4.0%	£1,425	−£192/month
15% (£45k)	£255,000	3.85%	£1,325	−£292/month
20% (£60k)	£240,000	3.75%	£1,234	−£383/month

Key insight: Moving from a 5% deposit to a 20% deposit saves about £383 a month — roughly £4,600 a year or £114,900 across a 25-year mortgage. The saving comes from both the smaller loan and the better rate.

How interest rates affect total cost

Small rate movements move total interest substantially. Below: a £270,000 mortgage over 25 years at different rates.

Interest rate	Monthly payment	Total repayable	Total interest
3.5%	£1,351	£405,420	£135,420
4.0%	£1,425	£427,500	£157,500
4.5%	£1,501	£450,420	£180,420
5.0%	£1,578	£473,580	£203,580
5.5%	£1,659	£497,610	£227,610

Key insight: A 1 percentage-point rate increase adds roughly £75–80 to the monthly payment on a £270,000 mortgage, or roughly £22,000 across a 25-year term.

Fixed vs variable rate impact

Fixed-rate mortgages

The interest rate is locked for the deal period (typically 2, 3, 5, or 10 years). The Bank of England's December 2025 Money & Credit release noted 53% of new mortgage commitments were 2-year fixed deals — up sharply from previous 5-year preference, reflecting market expectations of further rate cuts (which arrived on 30 April 2026).

Pros:

• Payment certainty
• Budgeting confidence
• Protection if rates rise

Cons:

• No participation if rates fall further within the fixed term
• Early Repayment Charges (typically 1–5%) apply if you exit before the fixed term ends

Best documented rates as of December 2025 (60% LTV):

• 2-year fixed: 3.55% (Santander)
• 5-year fixed: 3.76% (Santander)
• 10-year fixed: 4.35% (Nationwide)

Variable-rate mortgages

The rate changes with the Bank of England base rate (tracker) or the lender's Standard Variable Rate (SVR).

Pros:

• Benefit from further base-rate cuts
• Usually no Early Repayment Charges
• Typically unlimited overpayments

Cons:

• Payment uncertainty
• Risk of payment increases if base rate rises
• SVR is usually well above tracker pricing

Current pricing context (mid-2026):

• Best trackers: base rate + 0.5% = 4.25% (with base at 3.75%)
• SVR average: around 7% (down from 7.27% at end-2025)

How to use our mortgage calculator

1. Enter the property price (e.g. £300,000)
2. Enter the deposit (as £ or %)
3. Enter the interest rate (the calculator shows current averages)
4. Choose the term (typically 25–35 years)
5. See:
   • Monthly payment
   • Total amount repayable
   • Total interest paid
   • Full amortisation schedule

Calculate Your Mortgage Payments →

Levers that lower the monthly payment

1. Increase the deposit

Each additional £5,000 of deposit reduces the monthly payment by roughly £25–30 directly and can also push the loan into a better LTV band. Moving from 10% to 15% LTV typically secures a rate reduction of 0.15–0.25 percentage points.

2. Improve the credit profile

A higher credit score can shift the rate by 0.5–1.0 percentage points, which saves roughly £40–80 a month on a £270,000 mortgage. Registering to vote, paying bills on time, and clearing revolving credit utilisation are the standard mechanics.

3. Extend the mortgage term

A longer term reduces the monthly payment but increases total interest. On a £270,000 mortgage at 4.0%:

• 25 years: £1,425/month (£427,500 total)
• 30 years: £1,289/month (£464,040 total)
• Saves £136/month but costs £36,540 more in interest overall

4. Time the purchase

The Bank of England base rate has moved from 5.25% (August 2023 peak) through a series of cuts to 3.75% (30 April 2026). The MPC next meets on 30 July 2026. Mortgage pricing already reflects the current rate; further moves depend on inflation (CPI at 2.8% per the latest BoE summary) and labour-market data.

5. Make overpayments within the 10% allowance

Most fixed-rate UK mortgages allow up to 10% of the outstanding balance to be overpaid each year without triggering Early Repayment Charges. On the £270,000 example, an extra £100/month at 4.0%:

• Saves around £30,000 in interest over the full term
• Clears the mortgage about 4 years early

When professional advice is appropriate

Mortgage calculators provide accurate maths; a mortgage broker provides product matching. A broker can:

• Access exclusive lender deals not on the comparison sites
• Match products to specific circumstances (income type, credit profile, property type)
• Explain fees, ERCs, and offsets
• Handle the application process

Brokerage is particularly worth considering for:

• Self-employed applicants or those with complex income
• Buyers with adverse credit history
• Mortgages above 4.5× income
• First-time buyers unfamiliar with the process

Frequently asked questions

How much mortgage can I afford on my salary?

UK lenders typically offer 4 to 4.5 times annual gross income, subject to affordability and stress-testing. On a £40,000 salary that's £160,000–£180,000. Our affordability guide walks through the full assessment.

Are mortgage rates going down in 2026?

The Bank of England cut the base rate to 3.75% on 30 April 2026 and held at 3.75% on 18 June 2026, with CPI at 2.8%. Market expectations for the rest of 2026 vary; the next MPC meeting is 30 July 2026. Mortgage rates have continued to compress through 2026 as 2022/23 fixed deals roll off and pricing competition between lenders intensifies.

Is a 2-year or 5-year fixed deal better?

A 2-year fix allows re-mortgaging sooner if rates continue to fall; a 5-year fix locks in current pricing for longer and avoids re-mortgage fees in the interim. The Bank of England's December 2025 Money & Credit release showed 53% of new mortgage commitments were 2-year fixes, reflecting market expectations of further cuts (which arrived in April 2026).

Do I need a 20% deposit?

No. 5% deposit mortgages are widely available (subject to credit and affordability). The trade-off is a higher interest rate at 95% LTV — typically 0.7–1.0 percentage points above the 60% LTV best-buys.

Can I overpay my mortgage?

Most fixed-rate UK mortgages allow up to 10% of the outstanding balance to be overpaid annually without Early Repayment Charges. Trackers and SVR mortgages typically allow unlimited overpayments. The overpayment guide shows worked examples.

What happens when my fixed rate ends?

The loan automatically moves to the lender's Standard Variable Rate (SVR), which averages around 7% in mid-2026 (down marginally from 7.27% at end-2025) and is typically much higher than re-mortgaging onto a new fixed deal. Remortgaging within the final 6 months of the fixed term avoids the SVR jump.

How is mortgage interest calculated?

UK mortgage interest is calculated monthly on the outstanding balance. The monthly rate is the annual rate divided by 12. Early in the term, most of each payment goes to interest because the balance is high; later, most goes to capital because the balance has shrunk.

Is a 30-year mortgage better than 25 years?

A 30-year term lowers the monthly payment but increases total interest substantially. The 30-year route works best when monthly cash-flow flexibility matters more than total cost; making overpayments later effectively combines the lower commitment with shorter actual amortisation.

Related resources

• UK Mortgage Affordability Guide — how much you can borrow
• First-Time Buyer Deposit Guide — deposit requirements
• Mortgage Overpayment Guide 2026 — overpayment savings
• Fixed vs Variable Mortgages 2026 — pick the right product type
• Stamp Duty Calculator — purchase tax

---

Data sources:

• Bank of England: Bank Rate
• ONS: Private rent and house prices, UK
• Bank of England: Money & Credit statistical release

Last updated: 24 June 2026. Reflects Bank of England base rate of 3.75% (held 18 June 2026), April 2026 ONS UK average house price of £270,000, and the December 2025 best-buy snapshot still serving as the documented anchor for sub-3.6% fixed rates.

Disclaimer: The calculator and worked examples are estimates based on the rates and thresholds in force at the last updated date. Actual rates and total costs depend on the lender, applicant circumstances, fees, and product features. UK Calculator is not a mortgage broker or financial adviser; consult a qualified broker before deciding.