Initial deal versus reversion
A fixed or discounted rate normally lasts for a defined period. Model the payment at the follow-on rate and shop ahead of the deal end rather than assuming the opening payment lasts for the term.
UK mortgage and purchase analysis
Model the fixed deal, reversion payment, SDLT, overpayments and interest-only exit plan.
Built for pounds sterling and UK mortgage conventions. It supports capital repayment, interest-only and part-and-part structures, with current England and Northern Ireland residential SDLT bands or a manual Scotland/Wales tax input.
Decision guide
How to evaluate a UK mortgage deal
The headline fixed rate is only the first layer. Compare completion cash, the balance at the end of the deal, the reversion payment, overpayment rules and the plan for every pound of interest-only capital.
Repayment structure
Capital repayment reduces the balance over time. Interest-only reduces the monthly mortgage payment but requires a credible, separately monitored way to repay the capital at maturity.
Completion cash
Deposit, transaction tax, product fee, conveyancing, survey and moving costs are separate cash needs. Adding a fee to the mortgage means paying interest on it.
Tax scope
The built-in SDLT bands are for residential purchases in England and Northern Ireland. Scotland uses LBTT and Wales uses LTT, so enter a verified manual amount for those jurisdictions.
Overpayment restrictions
Many products permit some penalty-free overpayment, but allowances and early repayment charges vary by deal and year. Use the mortgage offer as the authority.
Get regulated advice
This planning model does not assess eligibility or recommend a product. A regulated mortgage adviser or lender must consider income, commitments, credit, term and repayment strategy.
Simple by design
Three steps to a clearer number.
Enter your details
Use realistic values in each field. You can change them anytime.
Calculate instantly
The formula runs locally, so there is no account or waiting time.
Use the result
Treat the answer as a practical estimate for your next decision.