Our UK Mortgage Affordability Calculator gives you a realistic estimate of how much you could borrow, what your monthly mortgage repayment might look like, and the property price your deposit and income will support. It models both repayment and interest-only mortgages and works for first-time buyers, home movers and remortgagors.

It is built for buyers planning a purchase, anyone weighing up a fixed or variable rate, and homeowners reviewing their loan-to-value (LTV) ahead of a remortgage. Combine it with our Stamp Duty Calculator to see the full upfront cost of moving, including SDLT and the deposit required.

The calculation follows the affordability approach used by most UK lenders. We start from your gross income and apply a typical 4 to 4.5× multiplier, adjusted for monthly debt commitments and dependants. Monthly repayments use the standard amortisation formula: M = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the loan, r the monthly interest rate and n the term in months. LTV is calculated as loan ÷ property price. Results are estimates only — final lending decisions depend on a full affordability assessment and credit check by your mortgage provider.