7.1% of property price
Extra monthly payment on top of your regular mortgage payment.
Optional — for affordability check
Monthly Payment
£1,744.67
Total Repayable
£628,081
Total Interest
£303,081
Loan Amount
£325,000
Popular Mortgage Calculations
Everything you need to know about mortgages in the UK
How is my monthly payment calculated?
Your monthly payment is calculated using the standard amortization formula. It takes your loan amount, interest rate, and term length to determine a fixed monthly payment that covers both interest and principal repayment. In the early years, more of your payment goes towards interest, while in later years the balance shifts towards paying off the principal.
What is LTV and why does it matter?
LTV (Loan-to-Value) is the ratio of your mortgage loan to the property value, expressed as a percentage. For example, if you buy a £250,000 property with a £25,000 deposit, your LTV is 90%. Lower LTV ratios typically mean access to better interest rates. Most lenders prefer an LTV of 80% or less, and you'll generally get the best rates at 60% LTV or below.
How do overpayments reduce my mortgage?
Overpayments go directly towards reducing your outstanding mortgage balance. Since interest is calculated on the remaining balance, even small regular overpayments can significantly reduce the total interest you pay and shorten your mortgage term. For example, overpaying £200/month on a £200,000 mortgage could save you tens of thousands in interest and cut years off your term.
What is a good mortgage interest rate?
Mortgage rates vary based on the Bank of England base rate, your LTV ratio, credit score, and whether you choose a fixed or variable rate. Fixed rates offer certainty over 2-5 years, while variable rates may be lower initially but can change. As of 2025, typical fixed rates range from around 4% to 6% depending on your circumstances. Always compare deals from multiple lenders.
Important: This calculator provides estimates for illustration purposes only. Actual mortgage offers depend on your credit history, lender criteria, and property valuation. For personalised mortgage advice, consult a qualified mortgage adviser.
This calculator uses official rates and thresholds from:
Last verified: February 2026 · Tax year 2025/26. Results are indicative — consult a qualified accountant for personalised advice.
Reviewed by M. Samiuddin Quadri, ACCA — Chartered Certified Accountant at Gladstone & Co. · Updated for the 2025/26 tax year.
Disclaimer: This calculator provides estimates based on current HMRC rates and thresholds for the 2025/26 tax year. It does not constitute professional tax, financial, or legal advice. Your actual liability may differ depending on your individual circumstances. Always consult a qualified accountant or tax adviser before making financial decisions. Read our terms
£250,000 Property with 10% Deposit at 5%
With a £25,000 deposit, your mortgage is £225,000 (90% LTV). Over 25 years at 5% interest, your monthly repayment is approximately £1,316. Total amount repaid: £394,800 — meaning you pay £169,800 in interest over the full term.
Tip: Overpaying by £100/month could save over £25,000 in interest and cut 3+ years off the term.
£400,000 Mortgage at 4.5% over 30 Years
Monthly repayment: approximately £2,027. Total repaid over 30 years: £729,720 — that’s £329,720 in interest. Compared to a 25-year term at the same rate (£2,224/month), you pay £395 less per month but £62,520 more in total interest.
£200,000 Mortgage at 6% — What If Rates Drop?
At 6%, monthly repayments on £200,000 over 25 years are approximately £1,289. If rates drop to 4.5% when you remortgage, payments fall to £1,112 — saving £177/month (£2,124/year). This shows why it’s worth checking remortgage options regularly.
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