How Lenders Look at Affordability

When you apply for a mortgage, the lender’s central question is straightforward: can you afford the repayments now, and would you still be able to if your circumstances changed? Affordability is not just about the size of your income. Lenders look at the whole picture — what you earn, what you spend, how you have managed credit in the past, and how much you are putting down as a deposit. Understanding how these pieces fit together can help you approach your mortgage application with confidence and avoid unnecessary surprises.

Assessing Your Income

Your income is the starting point, but lenders do not simply multiply your salary by a fixed number. They will verify what you earn and how stable it is. For employed applicants, this usually means payslips, P60s and bank statements showing your salary being credited. Lenders often use an income multiple — commonly around four to four and a half times your annual income — but this is a guide, not a guarantee. The actual figure depends on your outgoings and the lender’s own criteria.

If you are self-employed, a contractor, or you receive bonuses, commission or overtime, the assessment is more detailed. Lenders may average your income over two or three years and look at your SA302 forms or tax calculations. They want to see that your income is sustainable, not just a one-off spike.

• Basic salary: usually the most straightforward to assess.
• Bonus and commission: often considered if there is a consistent track record.
• Overtime: may be included, but lenders often use an average over several months.
• Self-employed income: typically based on net profit after allowable expenses.
• Other income: rental income, pensions or maintenance payments can sometimes be counted.

Your Regular Outgoings and Commitments

Lenders will also look closely at what you spend each month. They want to know how much of your income is already committed to other debts and essential living costs. This is where a realistic budget matters. If you have a car loan, credit card balances, a personal loan or student loan repayments, these will reduce the amount you can borrow. Lenders may also consider everyday spending such as childcare, travel, utilities and insurance.

Many lenders now use Open Banking or request bank statements to see your actual spending patterns. They are not looking for perfection, but they do want to see that you live within your means. A history of consistently spending more than you earn, or relying on an overdraft, can weaken your application. It helps to review your recent statements before applying and reduce any obvious discretionary spending where possible.

• Credit commitments: loan repayments, credit card minimums, car finance and overdrafts.
• Essential living costs: council tax, utilities, food, childcare and transport.
• Regular savings or investments: these can show financial resilience.
• Rent or current mortgage: proof that you have paid housing costs on time.

Credit History and Its Impact

Your credit history tells the lender how you have handled borrowing in the past. A clean record with payments made on time is reassuring. Missed payments, defaults, county court judgments or a history of payday loan use can raise concerns. Lenders also check that you are on the electoral roll at your current address, as this helps confirm your identity and stability.

It is worth checking your credit reports with the main agencies before you apply, so you can correct any errors and see what a lender will see. If you have had credit problems in the past, they do not automatically rule you out, but they may affect the amount you can borrow or the interest rate you are offered. A larger deposit or a smaller loan can sometimes offset a less-than-perfect credit history.

The Size of Your Deposit

Your deposit affects affordability in two ways. First, it determines your loan-to-value ratio — the percentage of the property price you are borrowing. A bigger deposit means a smaller mortgage, which is easier to afford and often comes with a lower interest rate. Second, it signals to the lender that you have a financial stake in the property and are less likely to fall into negative equity.

Most lenders offer deals from 5% or 10% deposits, but the best rates are usually reserved for those with 15%, 20% or more. If your deposit is smaller, the lender may apply stricter affordability checks or a higher stress test. Saving a little more before you apply can make a meaningful difference to what you can borrow and what you will pay each month.

Stress Testing and Lender Criteria

Finally, lenders must check that you could still afford your mortgage if interest rates rose. This is known as stress testing. They will typically assess whether you could cope with a rate increase of around one to three percentage points above your initial rate. They also consider how your circumstances might change — for example, if you took parental leave, changed jobs or faced an unexpected expense.

Each lender has its own affordability model, so it is worth speaking to a whole-of-market mortgage adviser who can compare criteria. What one lender declines, another may accept. Being prepared with clear documentation, a realistic budget and a sensible deposit will give you the best chance of a successful application and a mortgage you can comfortably afford over the long term.