Mortgage Calculator UK
UK mortgage calculator with Stamp Duty Land Tax (SDLT), LTV, repayment vs interest-only, and arrangement fees. First-time buyer and buy-to-let rates included.
Calculation Inputs
Use your initial fixed-rate period rate (e.g. 2 or 5-year fix).
Affects Stamp Duty Land Tax (SDLT) rates — England & N. Ireland.
Lender product fee. Typically £0–£2,000.
Results computed instantly — your data never leaves your device.
Live Results (GBP)
Real-TimeMonthly Payment
£1,556
Capital repayment
Loan Amount
£280,000
80.0% LTV
Stamp Duty (SDLT)
£0
Total Interest Paid
£186,899
Total Cost of Mortgage
£466,899
Total Purchase Cost
£350,999
Property + SDLT + upfront fees
Stamp Duty Land Tax Breakdown (England & N. Ireland)
Scotland uses Land and Buildings Transaction Tax (LBTT); Wales uses Land Transaction Tax (LTT) — rates differ.
How to Use the Mortgage Calculator UK
- 1
Enter the property value and your deposit — the LTV and loan amount calculate automatically.
- 2
Input your mortgage interest rate (use your initial fixed-rate period, e.g. 2 or 5-year fix).
- 3
Set the mortgage term (25 years is standard in the UK) and choose repayment or interest-only.
- 4
Select your buyer type — first-time buyer, home mover, or additional property — to calculate the correct Stamp Duty Land Tax (SDLT).
- 5
Add any arrangement fee and choose whether to pay it upfront or add it to the loan.
- 6
Review the monthly payment, Stamp Duty breakdown, and total purchase cost.
Formula & Mathematical Basis
Variable Key
LLoan amount (property value − deposit; + arrangement fee if rolled in)
rMonthly interest rate = Annual Rate ÷ 12 ÷ 100
nTotal number of monthly payments = Term Years × 12
SDLTStamp Duty Land Tax — banded tax on England & N. Ireland property purchases, calculated on marginal bands
📝 SDLT is calculated on marginal bands (not the whole price at the highest rate). First-time buyer relief applies only when the purchase price does not exceed £625,000.
Step-by-Step Examples
First-time buyer in England
Scenario: £350,000 property, £70,000 deposit (20% LTV), 4.5% rate, 25-year repayment term.
- 1.Loan: £350,000 − £70,000 = £280,000. LTV = 80%.
- 2.Monthly payment: £280,000 at 4.5%/12 over 300 months ≈ £1,556/month.
- 3.SDLT (first-time buyer): £0 on first £250,000; 5% on £100,000 = £5,000. Total SDLT = £5,000.
- 4.Wait — property is £350,000 < £425,000 so first-time buyer 0% applies to full £350,000. SDLT = £0.
- 5.Total purchase cost: £350,000 + £0 SDLT = £350,000 (plus solicitor/survey fees).
Home mover — standard SDLT
Scenario: £600,000 property, £150,000 deposit, 4.2% rate, 25-year repayment, home mover.
- 1.Loan: £450,000. LTV = 75%.
- 2.Monthly payment ≈ £2,440/month.
- 3.SDLT: 0% on £250,000 = £0; 5% on £350,000 (£250k–£600k) = £17,500. Total = £17,500.
- 4.Total purchase cost: £600,000 + £17,500 = £617,500.
Practical Use Cases
- First-time buyers budgeting total purchase costs including Stamp Duty
- Home movers comparing repayment vs. interest-only monthly cash flow
- Buy-to-let investors calculating Stamp Duty surcharge impact on yield
- UK expats returning home and assessing affordability at current rates
- Comparing true cost of different mortgage terms (20 vs 25 vs 30 years)
Common Pitfalls
- Confusing the initial fixed rate with the Standard Variable Rate (SVR) — after the fix ends, your payment will change, typically increasing substantially.
- Forgetting additional purchase costs: solicitor/conveyancing fees (£1,500–£3,000), survey (£500–£1,500), and removal costs.
- Interest-only without a repayment vehicle — the FCA requires lenders to verify a credible repayment strategy; lacking one is a serious financial risk.
- Assuming Help to Buy is still available — the equity loan scheme closed in March 2023.
- Ignoring the 3% SDLT surcharge when buying a second property — it applies even when letting out your former home.
Frequently Asked Questions
How is Stamp Duty Land Tax (SDLT) calculated in England?
SDLT is banded: 0% on the first £250,000; 5% on £250,001–£925,000; 10% on £925,001–£1,500,000; 12% above that. First-time buyers pay 0% up to £425,000 and 5% from £425,001–£625,000. Additional properties (buy-to-let, second homes) attract a 3% surcharge on every band.
Does Scotland or Wales use the same Stamp Duty?
No. Scotland uses Land and Buildings Transaction Tax (LBTT) with different thresholds and rates. Wales uses Land Transaction Tax (LTT). This calculator applies England & Northern Ireland SDLT rates — residents of Scotland or Wales should consult their respective Revenue authorities.
What is the difference between repayment and interest-only mortgages?
With a repayment mortgage, each monthly payment covers both interest and a portion of the capital — you own the property outright at the end. With an interest-only mortgage, monthly payments cover interest alone; you must repay the full capital at term end via a separate repayment vehicle (ISA, pension, property sale).
What LTV can I expect to get a mortgage?
Most UK lenders offer mortgages up to 95% LTV (5% deposit), though higher LTV products carry higher interest rates and fewer product options. The best rates typically start at 60% LTV. Above 90% LTV, options narrow significantly; lenders price in additional risk.
What is a mortgage arrangement fee?
An arrangement (or product) fee is charged by the lender for setting up the mortgage, typically £0–£2,000. You can pay it upfront or add it to the loan balance. Adding it to the loan means you pay interest on the fee for the full mortgage term, increasing total cost.
How does the Help to Buy scheme affect my mortgage?
The original Help to Buy Equity Loan scheme closed to new applicants in 2023. Buyers who used it have a government equity loan (typically 20%, or 40% in London) which affects their LTV calculation and will need to be repaid. This calculator models standard mortgages without equity loan components.
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