How Much Can I Borrow for a Mortgage?

Almost everyone starts with the same question, and almost everyone is given the same unhelpful answer: about four and a half times your income. It is a reasonable opening estimate and a poor prediction, because lenders do not actually work that way.

What lenders actually calculate

An income multiple is the output of an affordability assessment, not the input. The lender takes your income, subtracts your committed outgoings, applies a stress test to check you could still pay if rates rose, and works backwards to a maximum loan. The multiple is simply that figure divided by your income after the fact.

What counts against you

• Loans, car finance and buy-now-pay-later agreements
• Credit card balances — often assessed at a minimum monthly payment even if you clear them
• Childcare, school fees and maintenance payments
• Student loan deductions
• Ground rent and service charges on leasehold property

Clearing a modest car finance agreement can sometimes raise borrowing capacity by several times the balance you cleared. It is one of the few genuinely reliable levers available in the months before an application.

The stress test

Lenders must check you could still afford the mortgage at a higher rate than the one you are taking. The exact assumption varies between lenders, which is a large part of why two of them can look at identical figures and reach very different answers.

Why the answer differs by lender

Each lender sets its own view of how income is counted, how commitments are weighed, and how hard to stress the payment. Someone with a large bonus, self-employed income or a second job will see especially wide variation — which is the practical case for advice rather than approaching a single bank.

Our affordability calculator gives a rough starting figure. For anything beyond a simple salary, the useful number comes from someone who knows which lender to ask.