UK mortgage calculators
Mortgage Stress-Test Worksheet
Use a small scenario table to understand sensitivity rather than trying to predict one future mortgage rate.
Baseline row
Enter the verified balance, remaining term and current or proposed rate. Record the date and source for each input.
Rate rows
Add at least two higher rates and, if useful, a lower rate. These are scenarios rather than forecasts; choose increments that expose whether the household budget has headroom.
Term rows
Test a shorter and longer term separately. A lower monthly payment from a longer term can increase total interest and extend exposure.
Fee row
Show fees paid immediately and fees added to borrowing. Keep incentives separately visible so they do not conceal gross costs.
Household boundary
Compare results with income and committed expenditure outside this website. Include insurance, maintenance and an emergency margin rather than treating the calculator result as the whole housing cost.
Escalation trigger
Define the result that requires discussion with the lender or adviser—for example insufficient monthly headroom—before selecting a product or changing repayment strategy.
Sources and review standard
Calculations are independently implemented illustrations and were reviewed on 4 September 2026. We check factual boundaries against MoneyHelper's mortgage cost guidance, FCA consumer mortgage information and relevant lender documentation. Rates and product terms are never presented as live offers.
Download the mortgage stress-test worksheet
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.