Mortgage Affordability Calculator
Our mortgage affordability calculator estimates how much you may be able to borrow based on your income, outgoings, and the current lending criteria used by UK banks and building societies. It provides an indication for budgeting purposes — actual lending decisions depend on a full underwriting assessment by your chosen lender or a qualified mortgage adviser.
How Much Can I Borrow?
Estimate your maximum mortgage based on income, outgoings and deposit using standard UK lender income multiples.
How Lenders Assess Mortgage Affordability
UK mortgage lenders use two main tests. The first is an income multiple: most lenders offer between 4 and 4.5 times annual gross income for most borrowers, with some specialist lenders going to 5 or even 5.5 times for higher earners or professionals. The second is a stressed affordability assessment: lenders calculate whether you could still afford the mortgage if rates rose by 3% above your initial rate — the FCA-prescribed stress test introduced after 2014.
On a single income of £50,000, the maximum income-multiple borrow is approximately £225,000 at 4.5x. However, the stress test at rates 3% above the product rate (so around 7.5% if starting at 4.5%) may produce a lower figure — particularly for longer terms. Our calculator applies a realistic combined assessment.
What Reduces Borrowing Capacity?
Existing debt commitments — car finance, personal loans, credit card minimum payments — reduce the monthly payment your lender believes you can afford, and therefore the maximum mortgage. Each £200 per month of committed debt typically reduces borrowing capacity by £30,000 to £40,000. Childcare costs, school fees, and ground rents are also factored in by many lenders.
Deposit size matters too. A 10% deposit gives access to a wider range of products than a 5% deposit, and a 25% deposit typically unlocks the best rates. The Loan-to-Value (LTV) ratio directly affects the interest rate offered — lower LTV means lower rate, meaning lower monthly payment, meaning a slightly higher maximum loan.
Frequently Asked Questions
Yes. While income multiples set the upper limit, a poor credit history can result in lenders offering less than the maximum multiple, applying a higher interest rate, or declining entirely. Checking your credit report before applying and correcting any errors can improve the outcome.
Joint applications use the combined income of both applicants. A couple earning £35,000 each can borrow approximately £315,000 at 4.5x combined income — compared with £157,500 each individually. Lenders also assess both credit profiles, so any adverse credit on one applicant can affect the whole application.
First Homes offers qualifying first-time buyers new-build homes at a minimum 30% discount to market value, with the discount protected in perpetuity. The scheme reduces the purchase price, the deposit required, and the mortgage amount — but properties must meet specific criteria and eligibility rules apply. Use our Stamp Duty Calculator to check the SDLT position on any first-time buyer purchase.
Most high street lenders require the mortgage to be repaid by age 70 or 75, which limits the term available to older borrowers. Specialist equity release and retirement interest-only products exist for older borrowers but carry different risks and costs.
The minimum deposit for most mainstream mortgages is 5% of the purchase price. At 5% LTV, product choice is limited and rates are higher. A 10% deposit opens significantly more products. 15–25% gives access to the best rates. Our Mortgage Deposit Calculator shows how long it takes to save any deposit target at different savings rates.
Enter individual or combined gross income and any existing committed debt repayments (loans, car finance, credit card minimums). Lenders assess affordability on a net income basis after existing commitments, not just salary multiples alone. The LTV input (loan to value) affects which rate tiers you access — 60%, 75%, and 80% LTV thresholds typically represent the most significant rate improvements. Results show the range of borrowing likely available across the market, from conservative (4× income) to higher-end (4.5-5× for certain professions). Use this as a planning guide before speaking to a broker — an agreement in principle from a specific lender will involve a full credit assessment and may differ from this estimate.
Important Information
This calculator is provided for general information and planning purposes only. It does not constitute financial or tax advice and should not be relied upon as such. Figures are indicative estimates based on simplified, publicly available criteria and stated assumptions. Actual results depend on your full circumstances. See our Disclaimer for further information.