UK mortgage calculators
Mortgage Calculators
Choose the question you want to explore. All results are estimates and use only the figures you enter.
Mortgage Overpayment Calculator
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Overpay Mortgage or Save Calculator
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Remortgage Break-Even Calculator
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Mortgage Repayment Calculator
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Mortgage Rate Shock Report
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Interest-Only vs Repayment Calculator
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Mortgage Fee vs Lower Rate Calculator
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Prepare one input pack
Write down the statement date, balance, remaining term, current rate, deal end date, early-repayment charge, penalty-free overpayment allowance and all proposed product fees. Reuse the same dated figures across calculators so results can be reconciled.
Compare outputs consistently
Separate monthly cash flow from total cost and remaining balance. Record whether a fee is paid upfront or added to the mortgage, and use the same comparison period for competing deals. A lower initial payment is not automatically a lower overall cost.
When to obtain regulated advice
These illustrations cannot assess affordability, eligibility or suitability. A regulated mortgage adviser or lender can consider income, commitments, credit information, product rules and personal circumstances.
Editorial responsibility
Published by Acerville Sparks Limited. Software assists research, drafting and automated formula testing. Primary sources, assumptions and limitations are shown so readers can inspect the work. No independent mortgage professional or financial adviser review is claimed. Reviewed 4 September 2026.