Mortgage Calculator
Calculate payments, compare overpaying vs investing, and check stamp duty.
Mortgage Calculator
Calculate mortgage payments, overpayments, stamp duty, and compare remortgage deals. See how much you could save.
Instant results • Your data stays private • No sign-up required
Mortgage basics
Enter the details of the property and mortgage. Everything else updates as you tweak.
Can you afford it?
Lenders typically lend up to 4.5ร your annual income, minus debt commitments. Quick check below.
Stamp duty / land tax
Tax on buying property. Different rules for England/NI, Scotland, and Wales.
Overpayments
Pay extra each month or as a lump sum. See how much interest you save and how much sooner you'll be mortgage-free.
Mortgage balance over time
Overpay vs Invest
If you have spare cash each month, is it better to overpay your mortgage or invest in a Stocks & Shares ISA? Depends on the maths.
Overpay, then invest freed cash
- Interest saved: โ
- Mortgage paid off: โ
Invest alongside mortgage
- Total contributions: โ
- Investment growth: โ
Both scenarios assume the same total monthly cash commitment โ only the routing differs.
Comparison
Remortgage compare
Compare your current mortgage to a new deal. Includes Early Repayment Charges and arrangement fees so you can see if switching actually saves money.
Current deal
New deal
Amortization schedule
Month-by-month breakdown showing how each payment splits between interest and capital.