Mortgage affordability calculator
Find out how much you could borrow based on your income. See the range lenders typically offer and what your monthly payments might look like at each level.
Just because a lender will offer you a certain amount does not mean you should borrow that much. Peter would say to work backwards from the monthly payment you are genuinely comfortable with, not forwards from the maximum you can get. The stress test section above is the number to pay most attention to.
Income multiples
Most lenders offer between 4x and 4.5x your income. Some will go to 5x or 5.5x for high earners or certain professions. 3x is the conservative end.
What lenders actually check
Income multiples are a starting point. Lenders also check your credit score, monthly outgoings, existing debts, and how much deposit you have saved.
The stress test
Lenders must check you could afford the mortgage if rates rose significantly. This is why being approved for the maximum amount does not always mean you should take it.
Get a mortgage in principle
Before viewing properties seriously, get a mortgage in principle from a broker. It gives you a reliable borrowing figure and shows sellers you are a credible buyer.
Please note: This calculator provides estimates based on standard income multiples and is for guidance only. Actual borrowing amounts depend on individual lender criteria, credit history, outgoings, and deposit size. Results are not a guarantee of lending. Always speak to a qualified mortgage adviser or broker before making any decisions. This is not financial advice.
Calculator results are estimates based on the information you enter and the assumptions built into the tool. They are illustrative only and should not be relied upon as accurate projections. Rates, thresholds and rules change regularly; always verify figures with an appropriate professional or official source before acting on them.
What is a mortgage affordability calculator?
A mortgage affordability calculator estimates how much a lender is likely to offer you based on your income and financial commitments. It does not guarantee a specific offer — lenders each have their own criteria and conduct detailed assessments – but it gives a reliable ballpark figure for planning purposes.
Most UK mortgage lenders currently apply income multiples of 4-4.5 times annual gross income for standard applications, with some lenders offering up to 5 or 5.5 times income for specific professions or loan sizes. The calculator applies these multiples to your income, then adjusts for your existing financial commitments (credit card balances, car finance, personal loans, other mortgages), which reduce the amount a lender will offer.
How to use this calculator
Annual income: Enter your gross annual salary before tax. If you are applying jointly, enter the combined gross income of both applicants. Include reliable additional income – bonuses, rental income, other employment, but note that lenders treat variable income more conservatively than salary.
Monthly commitments: Enter the total monthly payments on any existing debt – credit cards, car finance, personal loans, student loans. These reduce affordability because lenders assess the total monthly outgoing burden, not just the mortgage payment.
Deposit: Enter the deposit amount you have available. A larger deposit means a lower loan-to-value ratio, which typically means access to better interest rates and sometimes higher income multiples.
Reading the result: The calculator shows a typical borrowing range. The lower figure is a conservative estimate; the higher figure is what more generous lenders might offer. The actual offer will depend on your full application, credit history and the specific lender’s criteria.
What affects affordability beyond income
Credit history: A clean credit record with no missed payments, defaults, or CCJs allows access to the full range of lenders. Issues on the credit record reduce the number of available lenders and sometimes reduce income multiples.
Employment type: Employed applicants with a permanent contract are assessed most straightforwardly. Self-employed applicants typically need two to three years of accounts. Contractors, those on zero-hours contracts, or those recently changing employment, are assessed more cautiously.
Number of applicants: Joint applications combine both incomes, which typically increases the total borrowing available. Lenders assess both credit records.
Existing property: If either applicant already owns a property, the 3% additional stamp duty surcharge applies, and some lenders apply different criteria.
Frequently asked questions
Why might I be offered less than the calculator suggests? The calculator applies standard income multiples. Individual lenders also assess your spending patterns (from bank statements), your credit score, your employment stability, and their own risk appetite. Any of these can result in a lower offer than the income multiple alone suggests.
Can I get a mortgage on a single income? Yes – single-income applications are assessed on the same multiples. The total available borrowing is lower than with a joint application on equivalent combined income, which affects the property price range rather than eligibility.
What is a mortgage in principle? A mortgage in principle (also called an agreement in principle or decision in principle) is a written indication from a lender of how much they would be willing to lend, based on a soft or hard credit check. It is not a guarantee and is subject to full application, but it signals your borrowing range to estate agents and sellers. Use this calculator to estimate the figure before approaching a lender for a formal mortgage-in-principle.
Do student loans affect mortgage affordability? Plan 1 and Plan 2 student loans are automatically deducted from take-home pay, which affects the income figure lenders see on payslips. Some lenders also treat the outstanding balance as a liability. The effect is usually modest, but real – include your monthly student loan deduction in the commitments field for a more accurate estimate.
What counts as a deposit for affordability purposes? The deposit is the cash amount you are putting in at purchase, not the equity in an existing property (which is realised only on sale). For a first purchase, this is cash savings, a Lifetime ISA, or a gifted deposit. For a remortgage or home move, it also includes the equity from your existing property after the sale.
The information on this site is for educational and informational purposes only. Nothing on Be More Peter constitutes financial advice, and nothing should be treated as such. The calculators, articles and tools on this site are designed to help you understand financial concepts and run indicative numbers - they are not a substitute for professional advice tailored to your specific circumstances. Before making any financial decision - including decisions about mortgages, pensions, investments, savings or insurance — you should seek independent financial advice from a qualified adviser who is authorised and regulated by the Financial Conduct Authority (FCA). Calculator results are estimates based on the information you enter and the assumptions built into the tool. They are illustrative only and should not be relied upon as accurate projections. Rates, thresholds and rules change regularly - always verify figures with an appropriate professional or official source before acting on them. Be More Peter is not authorised or regulated by the FCA. The content on this site does not constitute a financial promotion.
Related tools and posts
- LTV calculator — see which rate tier your deposit achieves
- Stamp duty calculator — calculate the tax on your purchase
- House deposit calculator — how long to save your deposit at your rate
- How much can I borrow for a mortgage?
- First-time buyer guide
- What is a mortgage in principle?