How is my monthly mortgage payment calculated?

We use the standard amortisation formula: M = P * r(1+r)^n / ((1+r)^n - 1), where P is the loan amount, r the monthly interest rate, and n the number of months. The result is what you would pay each month on a repayment mortgage.

Does this calculator include UK stamp duty?

Yes. The calculator includes stamp duty for England & Northern Ireland (SDLT), Scotland (LBTT) and Wales (LTT), with first-time buyer relief applied automatically where eligible. Rates reflect April 2025 onward bands; verify current rates with HMRC, Revenue Scotland or the Welsh Revenue Authority before completing a purchase.

What deposit do I need for a UK mortgage?

Most UK lenders require a minimum 5 deposit. A larger deposit (15) usually unlocks better interest rates and lower monthly payments. The calculator shows your loan-to-value (LTV) ratio so you can see which lender tier you would qualify for.

Should I choose a repayment or interest-only mortgage?

Repayment mortgages pay off both interest and capital each month — at the end of the term you own the home outright. Interest-only mortgages are cheaper monthly but require a separate plan to repay the capital. The calculator supports both so you can compare.

Is this calculator financial advice?

No. This tool is a guide only. Always speak to an FCA-regulated mortgage broker before committing. Your home may be repossessed if you do not keep up repayments on your mortgage.

UK Mortgage Calculator with Stamp Duty (2026)

UK Mortgage Calculator

Work out your monthly payment, stamp duty & total cost. Get a free PDF report with the full breakdown.

Get the full breakdown — free PDF

Year-by-year amortisation
Stamp duty band-by-band
Overpayment savings calculator
Affordability indicators

This calculator is a guide only and not financial advice. Stamp duty rates shown are indicative — verify current rates with HMRC, Revenue Scotland or the Welsh Revenue Authority. Your home may be repossessed if you do not keep up repayments on your mortgage.

UK Mortgage Calculator with Stamp Duty (2026)

UK Mortgage Calculator

Get the full breakdown — free PDF

Your full mortgage breakdown

Stamp duty breakdown

Overpayment scenario

Year-by-year amortisation