Table of Contents
- How Lenders Work Out How Much Mortgage You Can Get
- Mortgage Affordability Based on Salary: What You Need to Know
- Using a Mortgage Affordability Calculator
- The Mortgage Deposit Calculator: How Your Deposit Changes Your Borrowing
- What to Expect from a Mortgage Affordability Assessment
- The Mortgage Application Process: From Enquiry to Offer
- How to Improve How Much You Can Borrow
- Conclusion
- Frequently Asked Questions
Last Updated: October 19, 2026
How Lenders Work Out How Much Mortgage You Can Get
Working out how much mortgage can I get is the first question most buyers ask, and the answer comes down to two tests lenders run side by side. This guide from Andrew Westwood Mortgages walks through both, in plain English.
The first test is a simple multiple of your income. The second is a detailed look at what you can actually afford each month. You need to pass both. Lenders do not publish their exact formulas, so treat any figure you get online as a starting estimate, not a promise.
Income multiples and the 4.5x rule
Most lenders will lend around 4 to 4.5 times your annual income. Some stretch further for higher earners or certain professions. A household earning £40,000 a year might be offered somewhere between £160,000 and £180,000 before other factors are applied.
The 4.5x rule is not a law. It is a common industry benchmark, and lenders can go above or below it.
The affordability stress test
Since the Financial Conduct Authority’s mortgage rules took effect, lenders must check you can still pay if rates rise. They test your repayments against a higher rate than the one you are offered.
If you pass on paper but fail the stress test, the loan shrinks or falls through. That is why a low monthly payment today does not guarantee approval.
Mortgage Affordability Based on Salary: What You Need to Know
Mortgage affordability based on salary is where most buyers start, and it is also where most estimates go wrong. Lenders look at gross income before tax, then subtract debts, bills and dependants.
A rough formula you can use:
Borrowing estimate = (annual income × 4.5) − existing credit commitments
So a £35,000 salary with a £200 monthly car loan might support roughly £155,000, not £157,500. Small debts add up.
Things that change the picture:
- Bonuses and overtime usually count only if they are regular and provable
- Childcare costs reduce what lenders think you can afford
- Credit card limits count against you even if you clear the balance
- Student loans are deducted from affordability
How self-employed income is treated
Self-employed buyers face a stricter process. Lenders typically want two to three years of accounts or tax calculations, and they often use an average of those years rather than your best one.
A common mistake is assuming your latest strong year will be used. It usually will not.
If your income varies, get your SA302 forms and tax year overviews ready before you apply. Lenders assess self-employed cases faster when the paperwork is complete, and gaps in the record are the main reason applications stall.
Using a Mortgage Affordability Calculator
A mortgage affordability calculator gives you a fast estimate, not an approval. It takes your income, debts and deposit, then applies a typical multiple and stress test.
Use it to set a realistic budget before you view properties. Then check the number with a broker, because calculators cannot see lender-specific rules.
What a good calculator should ask for:
- Gross annual income for all applicants
- Regular monthly credit commitments
- Deposit amount
- Term length in years
- Employment type
Run the numbers at a higher rate too. If the monthly payment still feels comfortable, you have room to absorb a rate rise.
The Mortgage Deposit Calculator: How Your Deposit Changes Your Borrowing
A mortgage deposit calculator shows how your deposit affects both the loan size and the rate you are offered. A bigger deposit lowers the loan-to-value ratio, which usually opens up cheaper deals.
| Deposit as % of property price | Loan-to-value | Typical effect on borrowing |
|---|---|---|
| 5% | 95% | Smallest loan, highest rates |
| 10% | 90% | More lenders willing to offer |
| 15% | 85% | Better rates start to appear |
| 20% | 80% | Wider choice, lower monthly cost |
| 25%+ | 75% or less | Best rates typically available |
The deposit does not just reduce the amount you borrow. It changes which lenders will consider you at all.
What to Expect from a Mortgage Affordability Assessment
A mortgage affordability assessment is the formal check a lender runs before approving your application. It combines your income, outgoings, credit file and the stress test into one decision.
Expect questions about subscriptions, school fees, travel and any regular commitments. Lenders now look closely at bank statements, so unexplained spending can slow things down.
Documents you will need
Have these ready before you apply:
- Photo ID and proof of address
- Last three months’ payslips
- Last two to three years’ accounts or SA302s if self-employed
- Three to six months of bank statements
- Proof of deposit source
- Details of any existing credit agreements
Do not move large sums into your account shortly before applying without a clear paper trail. Lenders must verify where the deposit came from, and unexplained transfers can delay or derail the application.
The Mortgage Application Process: From Enquiry to Offer
The application process runs from first enquiry to formal offer in a set sequence. Knowing the stages removes most of the stress.
- Enquiry and budget check. You set a realistic borrowing figure.
- Agreement in principle. A lender confirms it would likely lend to you.
- Full application. You submit documents and the lender runs its assessment.
- Property valuation. The lender checks the home is worth the price.
- Underwriting. The lender reviews everything and confirms the offer.
- Mortgage offer issued. You are cleared to proceed to completion.
An agreement in principle is not a guarantee. It signals intent, and the full assessment still applies.
At Andrew Westwood Mortgages, we handle this sequence with you one to one, with no call centres and no handing off between departments. We explain each stage in plain English so you know what is happening and why.
How to Improve How Much You Can Borrow
Boosting your borrowing power usually comes down to a few practical moves. None of them are glamorous, but they work.
- Clear small debts. Paying off a car loan or card balance can lift your limit more than a pay rise.
- Reduce credit limits. Lenders count unused limits as potential debt.
- Save a larger deposit. Moving from 10% to 15% often improves both the rate and the maximum loan.
- Fix errors on your credit file. Check it before applying, not after.
- Add a second applicant. Joint applications combine incomes.
- Avoid new credit. Do not take out a loan or phone contract mid-application.
A common mistake is applying to several lenders at once to compare offers. Multiple full applications leave marks on your credit file. Use an agreement in principle instead.
The single biggest lever on how much you can borrow is usually your existing debt, not your salary. Clearing commitments before you apply often does more than waiting for a pay rise.
Conclusion
The honest answer to how much mortgage you can get depends on your full picture, not a single multiple. Income, debts, deposit and the stress test all pull on the final figure, and estimates online only get you part of the way.
That is where we come in. At Andrew Westwood Mortgages, we search many lenders and give you personalised advice, so you understand your options and make decisions you are comfortable with. We support first-time buyers, home movers, remortgagers and the self-employed, and we are authorised and regulated by the Financial Conduct Authority.
Get started with Andrew Westwood Mortgages and find out what you can genuinely borrow. Let’s talk.
Frequently Asked Questions
How much mortgage can I get based on my salary?
Lenders typically use income multiples of around 4 to 4.5 times your salary, but they also run a detailed affordability assessment that looks at your outgoings, debts, and lifestyle costs. Two people on the same salary could be offered different amounts because of their spending habits or credit history. Use a mortgage affordability calculator for a rough idea, then speak to an adviser who can match you with lenders that fit your full picture. The exact multiple varies by lender and circumstances.
Does a mortgage affordability calculator give an accurate borrowing amount?
A mortgage affordability calculator gives a useful starting estimate, but it cannot replicate a lender’s full assessment. Calculators usually ask for income, deposit, and regular outgoings, then apply a typical income multiple. Real lenders also check credit file data, stress-test your repayments at higher interest rates, and may treat bonuses or self-employed income differently. Use the calculator to set a budget range, then get a personalised decision in principle from a broker or lender for a more reliable figure.
Can I borrow more if I have a larger deposit?
Yes, a larger deposit can increase how much you can borrow because it reduces the loan-to-value ratio, which often opens up lower interest rates and more lender options. However, the maximum loan amount is still primarily driven by your income and affordability. A mortgage deposit calculator helps you see how different deposit amounts affect the loan size you need. Speak to an adviser to understand the trade-off between deposit size and borrowing capacity for your situation.
What outgoings affect how much mortgage I can get?
Lenders look at regular commitments such as credit card repayments, personal loans, car finance, student loan repayments, childcare costs, and even spending on subscriptions or leisure. They also consider whether you have dependants or will take on a new mortgage payment alongside existing debts. Reducing or clearing debts before applying can improve your borrowing potential. A mortgage affordability assessment will review your bank statements and credit report to build a full picture.