🏠 Repayment · Interest-Only · Stamp Duty · Overpayment · LTV Bands
UK Mortgage Calculator
Calculate monthly repayments, total interest, and Stamp Duty Land Tax (SDLT) for your UK property purchase. Supports repayment, interest-only, and overpayment scenarios.
Mortgage Details
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£
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LTV: 80%
% /yr
yrs
Stamp Duty (SDLT)
Overpayments
Add monthly overpayment
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Enter your mortgage details above
Monthly payment, stamp duty, and amortisation will appear here
Monthly
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Stamp Duty
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LTV
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Total Interest
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All-In Cost
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incl. SDLT
Loan-to-Value (LTV)
Lower LTV = better rates
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0% LTV60%75%90%100%
Stamp Duty Land Tax Breakdown
| Band | Rate | Taxable Amount | Tax |
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Total SDLT Due
£0
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Balance Over Time
How UK Mortgages Work
A mortgage in the UK is a secured loan used to purchase property, where the property itself acts as collateral. The vast majority of UK mortgages are repayment mortgages, where monthly payments cover both the outstanding capital (principal) and interest, gradually paying down the debt over the term. Interest-only mortgages — where you pay only the interest each month and must repay the full loan at the end — were common before 2008 but are now primarily used for buy-to-let properties. For related calculators, see our Mortgage Calculator and Amortisation Calculator.
The Monthly Repayment Formula
Repayment Mortgage Formula
Monthly Payment = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]
Where: P = loan amount, r = monthly rate (annual rate ÷ 12), n = term in months
Example: £240,000 at 4.5% for 25 years:
r = 0.045/12 = 0.00375, n = 300
Monthly = £240,000 × [0.00375×(1.00375)³⁰⁰] / [(1.00375)³⁰⁰ − 1] = £1,333/mo
Interest-only: Monthly = Loan × (Annual Rate / 12). Capital due in full at end of term.
Stamp Duty Land Tax (SDLT) Rates in England & Northern Ireland (2025)
| Purchase Price Band | Standard Rate | First-Time Buyer Rate | Additional Property |
|---|---|---|---|
| Up to £125,000 | 0% | 0% (up to £300k) | 5% |
| £125,001 – £250,000 | 2% | 0% (up to £300k) | 7% |
| £250,001 – £925,000 | 5% | 5% | 10% |
| £925,001 – £1,500,000 | 10% | 10% | 15% |
| Above £1,500,000 | 12% | 12% | 17% |
Note: First-time buyers get full relief on the first £300,000 and pay 5% on the portion from £300,001 to £500,000. Properties over £500,000 do not qualify for first-time buyer relief. Scotland uses LBTT (Land and Buildings Transaction Tax); Wales uses LTT (Land Transaction Tax) — different rates apply. Non-UK residents pay a 2% surcharge on top of all rates. Additional/second properties have a 5% surcharge.
Understanding LTV Bands and Mortgage Rates
The Loan-to-Value (LTV) ratio is the most important factor in your mortgage rate. Lower LTV = less risk for the lender = lower interest rate offered. UK lenders typically offer their best "headline rates" at 60% LTV:
60%
Best available rates. 40% deposit or equity required.
75%
Competitive rates. 25% deposit required.
80%
Standard rates. 20% deposit — most common first-time buyer tier.
85%
Higher rates. 15% deposit. Fewer lenders available.
90%
Limited options. 10% deposit. Rates significantly higher.
95%
Maximum mainstream LTV. 5% deposit. Highest rates. Government schemes may help.
Frequently Asked Questions
Common questions about UK mortgages, stamp duty, and buying property in England
UK mortgage lenders typically offer between 4× and 4.5× your annual income as a maximum loan. Some specialist lenders offer up to 5× or 5.5× for high earners or professionals. For joint mortgages, both incomes are usually combined. The actual amount depends on: your credit score, existing debts and commitments, employment type (employed vs self-employed), the property type, and the lender's affordability assessment. Lenders are legally required under the Mortgage Market Review (MMR) rules to stress-test your affordability at a higher interest rate (typically 2–3% above the offered rate) to ensure you can manage if rates rise. Use our Salary Calculator to understand your income, then multiply by 4–4.5 as a rough maximum borrowing estimate.
Stamp Duty Land Tax (SDLT) is a tax paid to HMRC when you buy property or land in England or Northern Ireland (Scotland has LBTT; Wales has LTT). It is calculated on a tiered (slice) basis — each rate applies only to the portion of the purchase price within that band, not the whole price. Example for a £300,000 purchase (standard rates, 2025): 0% on first £125,000 = £0; 2% on £125,001–£250,000 = £2,500; 5% on £250,001–£300,000 = £2,500. Total SDLT = £5,000. First-time buyers pay 0% up to £300,000 and 5% from £300,001 to £500,000, with no relief on purchases over £500,000. SDLT must be paid within 14 days of completion. This calculator applies all current rates automatically based on your buyer type selection. For comparison, see our Income Tax Calculator.
A repayment mortgage means each monthly payment covers both interest and a portion of the loan capital. By the end of the term, you have paid off the entire mortgage and own the property outright. An interest-only mortgage means monthly payments cover only the interest — the original loan balance remains unchanged throughout the term and must be repaid in full at the end (typically from a repayment vehicle like an ISA, pension, or property sale). Interest-only gives lower monthly payments but you never reduce the debt. Example on £200,000 at 4.5% over 25 years: repayment = ~£1,111/month; interest-only = £750/month but £200,000 still owed at the end. Interest-only residential mortgages are now rare due to FCA regulations introduced after 2014; they are mainly available for buy-to-let. Most UK homeowners use repayment. See our Amortisation Calculator for a full repayment schedule.
Most UK mortgages allow overpayments of up to 10% of the outstanding balance per year without early repayment charges (ERCs). Any overpayment goes directly to reducing the outstanding capital, which reduces the interest charged in subsequent months. Over time, this compounds: smaller balance → less interest → faster payoff. Example: on a £200,000 mortgage at 4.5% over 25 years, overpaying by £200/month saves approximately £22,000 in interest and cuts 4 years off the term. Before overpaying, check your mortgage terms for the annual overpayment limit (usually 10%) — exceeding it may trigger ERCs of 1–5% of the overpayment amount. Fixed-rate mortgages typically have stricter limits during the fixed period. Tracker and variable rate mortgages often allow unlimited overpayments. Use the overpayment toggle in this calculator to model your savings.
Use the rate that best represents your situation: (1) Current quoted rate — if you have a mortgage offer or are comparing specific products, use the exact rate offered; (2) Bank of England Base Rate (the base rate) — tracker mortgages charge base rate + a margin (e.g. base + 0.75%); (3) Market average — as of mid-2025, UK 2-year fixed rates are broadly in the 4–5% range for 60–75% LTV, with 5-year fixes slightly lower. Rates vary significantly by LTV: a 60% LTV mortgage may be 0.5–1% cheaper than a 90% LTV mortgage; (4) Long-term planning rate — for a 25-year projection, many financial advisers suggest using 5–6% as a conservative long-term assumption to stress-test affordability. Always get a personal mortgage illustration (KFI/ESIS) from a regulated adviser or lender for accurate rates. Our calculator is for illustration only. For income vs repayment affordability, also check our Salary Calculator.
Note: The Help to Buy Equity Loan scheme closed to new applications in October 2022. Under the scheme (while active), the government lent first-time buyers up to 20% of the property price (40% in London) interest-free for 5 years, allowing buyers to secure a 75% LTV mortgage with just a 5% deposit. The equity loan had to be repaid on sale or full payoff, calculated as the same percentage of the property's market value at that time (meaning if the property rose in value, more was repaid). Since its closure, alternatives include: the Mortgage Guarantee Scheme (government-backed 95% LTV mortgages), First Homes (discounted new-build properties for first-time buyers), Shared Ownership (buy a share of a property), and the Lifetime ISA (25% government bonus on savings up to £4,000/year, for first home purchase). Check the GOV.UK website for the latest schemes. For current mortgage calculations, use this calculator with your actual deposit as the deposit amount.