About this calculator
The Mortgage Affordability Calculator estimates how much you may be able to borrow based on income, deposit, debts, and affordability assumptions. It helps turn household income into a realistic property budget before speaking to a lender or broker. Use it to compare single and joint applications, deposit levels, loan-to-value bands, and the effect of regular commitments.
Affordability methodology
Mortgage affordability is usually estimated from income multiples and then constrained by deposit, monthly commitments, loan-to-value, and stress-tested payments.
- maximum loan estimate = eligible income x income multiple
- property budget = estimated loan + deposit
- loan-to-value = mortgage / property value
How affordability is estimated
- Enter household income.
- Enter deposit and regular debt commitments.
- The calculator estimates borrowing using an income multiple.
- It compares the deposit against the implied property value.
- It highlights affordability as a planning estimate, not a lender decision.
Worked examples
Single applicant
Input: Income GBP 50,000, multiple 4.5
Calculation: 50,000 x 4.5
Result: Estimated borrowing around GBP 225,000 before lender adjustments
Joint applicants
Input: Combined income GBP 80,000, multiple 4.5
Calculation: 80,000 x 4.5
Result: Estimated borrowing around GBP 360,000 before commitments
Deposit effect
Input: Loan GBP 225,000, deposit GBP 25,000
Result: Estimated property budget around GBP 250,000
How mortgage affordability works in the UK
Mortgage affordability is not based only on salary. UK lenders look at income, deposit, existing debts, childcare, regular spending, credit history, property type, loan-to-value, and how payments would look if rates changed. The calculator gives a planning estimate before a lender or broker runs a full assessment.
The result is best used to set a sensible property search range. A lender may offer more or less depending on underwriting rules, product type, and the evidence you provide.
Main affordability components
Several moving parts determine how much you may be able to borrow. Looking at them separately makes the result easier to understand.
- Income multiple
- A rough borrowing estimate often starts with household income multiplied by a factor such as 4 to 4.5. Some lenders may go higher or lower depending on risk and circumstances.
- Loan-to-value
- Loan-to-value compares the mortgage balance with the property value. A lower LTV usually means a larger deposit and may unlock better rates.
- Monthly commitments
- Credit cards, car finance, personal loans, childcare, maintenance payments, and other commitments can reduce the amount a lender considers affordable.
- Stress testing
- Lenders may test whether payments would remain affordable at a higher rate. This can limit borrowing even when current payments look manageable.
Affordability is not the same as comfort
A maximum borrowing estimate does not mean the mortgage is comfortable. Home ownership also brings stamp duty, insurance, moving costs, repairs, bills, service charges, furniture, and emergency expenses. A safer budget leaves room for rate changes and life events.
Documents lenders usually review
A calculator can estimate borrowing, but lenders make decisions from evidence. Before applying, borrowers are usually asked for payslips, bank statements, proof of deposit, ID, address history, credit commitments, and sometimes employment contracts or accounts.
- Employed income
- Lenders often review recent payslips and bank statements. Overtime, bonus, and commission may be averaged or discounted.
- Self-employed income
- Self-employed applicants may need tax calculations, accounts, business bank statements, and evidence covering two or more years.
- Credit commitments
- Loans, credit cards, car finance, childcare, maintenance payments, and other commitments can reduce available borrowing.
- Deposit source
- Savings, gifts, sale proceeds, and other deposit sources may need evidence for anti-money-laundering checks.
Loan-to-value and rate bands
Affordability and mortgage rates are closely linked to loan-to-value. A buyer with a 5% deposit is borrowing 95% of the property value and may face fewer products or higher rates. A buyer with a 20% or 25% deposit often has access to wider product choice. Moving from one LTV band to another can sometimes save more than expected.
Common mistakes and edge cases
- Assuming every lender uses the same income multiple.
- Ignoring credit cards, loans, childcare, and lease payments.
- Forgetting that rates and stress tests affect affordability.
- Treating a maximum loan as a comfortable budget.
- Ignoring stamp duty and moving costs.
Limitations
This calculator provides an estimate only and is not financial or tax advice.
- It does not represent a mortgage offer.
- Lender affordability models vary and can change.
Frequently asked questions
How many times my salary can I borrow?
Many estimates use around 4 to 4.5 times income, but actual lender decisions vary.
Does deposit affect affordability?
Yes. A larger deposit can reduce loan-to-value and may improve available rates.
Do debts reduce borrowing?
Yes. Regular commitments can reduce the monthly payment a lender considers affordable.
Can this confirm I will be approved?
No. Approval depends on lender criteria, credit checks, documents, and property valuation.
Should I borrow the maximum?
Not always. Leave room for rate rises, maintenance, insurance, and life changes.
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- Stamp Duty Calculator
- Refinance Calculator