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UK Mortgage & Stamp Duty Calculator

Estimate your monthly repayments, total interest, stamp duty (SDLT, LBTT or LTT) and the impact of overpayments.

Showing example figures. Edit any field with your own.

Property & mortgage

£
£

LTV: · Loan:

%
£

Most lenders allow up to 10% overpayment per year without penalty.

Stamp duty

Your mortgage

Monthly
Total interest
Total repaid
Loan amount
Loan-to-value
Stamp duty
Termy m

With overpayments you'd save in interest and clear the loan early.

Balance over time

Yearly summary

YearInterestCapitalBalance end

Stamp duty 2026/27 reference

England / NI (SDLT): 0% to £125k, 2% £125k–£250k, 5% £250k–£925k, 10% £925k–£1.5m, 12% above. First-time buyer relief up to £500k.

Scotland (LBTT): 0% to £145k, 2%–12% banded above. FTB threshold £175k. ADS surcharge 8%.

Wales (LTT): 0% to £225k, 6%–12% above. No FTB relief — already higher threshold.

See gov.uk, Revenue Scotland, WRA.

Not sure if you're getting the best rate? A can compare deals you can't get direct, including buy-to-let and remortgage offers.