10 common mistakes to avoid when applying for a mortgage

Applying for a mortgage can feel like a checklist exercise—until you realise how many small details can affect the outcome. Lenders assess affordability, risk and reliability, and they expect information to be accurate and consistent.

Below are 10 common mistakes that can slow things down, create avoidable questions, or reduce the options available.

1. Not shopping around for the right mortgage

Many borrowers focus on a headline interest rate and miss the bigger picture: total cost, fees, repayment structure, and how the deal fits your plans.

A mortgage broker can help you compare suitable options across lenders, taking into account the features that matter to you—rather than relying on a single offer.

2. Overlooking your credit file

Your credit history is one of the first things lenders review. If there are errors, missed payments, or accounts you didn’t realise were being reported, it can cause delays or affect the decision.

Before you apply, review your credit file and address any inaccuracies. It’s also worth being cautious about making major financial changes during the application window.

3. Not having a realistic budget for monthly repayments

Affordability isn’t just about whether you can borrow—it’s about whether you can comfortably repay.

A common mistake is planning around an estimated payment without considering how your wider finances will cope. Include existing commitments (such as credit cards, car finance, and other loans) and think about what happens if your circumstances change.

4. Underestimating how much deposit you need

Deposit size can influence both the range of mortgages available and the overall cost of the loan.

If your deposit is tight, you may have fewer options. It’s also important to consider what you’ll still need after completion—moving costs, initial household expenses, and any immediate repairs.

5. Being unclear or inaccurate about your finances

Mortgage applications require evidence. If income or outgoings are misstated—or if supporting documents don’t match what’s been declared—lenders may ask for clarification, which can extend timelines.

Being prepared with the right information helps keep the process moving. Consistency across forms, statements and payslips matters.

6. Not considering an agreement in principle (where appropriate)

An agreement in principle (sometimes called a decision in principle) can help you understand the type of borrowing you may be considered for before you commit to a property.

While it’s not the final mortgage offer, it can reduce uncertainty when making decisions and help you plan your next steps more confidently.

7. Not fully understanding the mortgage terms

It’s easy to skim over the details—especially when you’re focused on affordability and speed.

Before committing, make sure you understand key terms such as:

• the interest rate type (for example, fixed or variable)
• the length of any introductory period
• fees and charges
• repayment method and how overpayments work
• what happens at the end of the deal

A clear understanding helps you avoid surprises later.

8. Forgetting the wider cost of owning a home

The monthly mortgage payment is only part of the picture. Homeownership also brings costs such as buildings insurance and ongoing maintenance.

If you only budget for the mortgage, it’s easier to run into difficulties once the property is yours.

9. Not planning for completion and upfront costs

Many applicants focus on deposit and monthly payments, then realise too late that there are additional costs to cover around completion.

These can include items such as stamp duty (where applicable), solicitor and conveyancing fees, lender-related fees, and survey costs. Having funds set aside can prevent last-minute issues.

10. Not checking mortgage paperwork carefully

Mortgage documents contain important conditions. Signing without fully understanding the terms can lead to confusion about responsibilities and expectations.

Take time to review the paperwork and ensure you’re comfortable with the obligations—especially around repayment, fees, and any conditions attached to the offer.

A final note on keeping your application strong

The best mortgage applications tend to be well-prepared, consistent and realistic. Avoiding the mistakes above can help reduce friction and give lenders the information they need to assess your application properly.

Your home may be repossessed if you do not keep up repayments on a mortgage or any other debt secured on it.