Estimate how much you could borrow.

How it works

Start with an income multiple, then add affordability

Simple mode is the default. It applies traditional multiples of 4.0 and 4.5 to eligible annual income, then caps the result if the deposit cannot support it at the maximum loan-to-value entered.

Opening the Advanced affordability model activates a third constraint. It estimates net monthly income, subtracts debts, essential spending, dependant costs and a safety buffer, then converts a stressed affordable payment into a mortgage amount over the selected term. The lowest applicable income, affordability or deposit limit constrains the advanced result.

For joint applicants, eligible income is combined. The calculator includes basic salary in full and, by default, includes 50% of entered bonus, overtime and commission. A lender can use different evidence periods, inclusion percentages and criteria for variable or self-employed income.

Understanding your result

The range is a model, not an agreement in principle

The conservative and typical-upper scenarios use income multiples of 4.0 and 4.5 respectively. In simple mode they are capped only by deposit and LTV. Advanced mode also caps them using modelled monthly affordability, while its custom scenario uses the multiple you enter. These labels describe calculator assumptions, not the policy of every lender or a promise that high loan-to-income borrowing is available.

The normal monthly repayment uses the expected interest rate. When Advanced is active, the stressed repayment uses the separate stress rate to test a less favourable scenario. Lenders must consider affordability and may need to account for likely future interest-rate increases, but they design their own assessments within the applicable rules.

Loan-to-income divides the estimated mortgage by eligible annual income. Loan-to-value divides it by the modelled property budget. A larger deposit generally reduces LTV, but product availability, pricing, valuation and property eligibility remain lender-specific.

Worked example

Simple and advanced results use different constraints

For one applicant earning £40,000 with a £30,000 deposit, simple mode shows a £160,000 to £180,000 range using 4.0 and 4.5 income multiples. The upper illustration gives a £210,000 property budget and approximately 85.7% LTV. At the entered 4.5% rate over 25 years, its modelled monthly repayment is about £1,001.

Opening Advanced activates its default £200 monthly debt payments, £900 essential spending, £250 safety buffer and 7.5% stress rate. The calculator estimates net monthly income of about £2,693 using its 2025–26 tax assumptions and allocates 75% of the remaining modelled disposable income to the stressed payment.

Those advanced assumptions support an illustrative mortgage of about £136,331, with a normal payment of about £758 and stressed payment of about £1,007. Monthly affordability is therefore the advanced binding constraint. Both results exclude purchase costs and are not lending decisions.

Assumptions and limitations

A lender will assess more information

The Advanced monthly net-income estimate uses 2025–26 Income Tax and employee National Insurance rules for the selected UK region. Tax does not constrain simple mode. The advanced estimate does not include pension deductions, student loans, benefits, maintenance payments or every household expense unless their cost is reflected in the fields you enter.

The calculator does not check credit history, employment status, income evidence, probation periods, residency, age policy, source of deposit, property construction, lease terms or lender-specific product criteria. It also does not model future changes in earnings, expenditure or tax rules.

A longer term can reduce the modelled monthly payment but usually increases total interest and may extend beyond a lender’s age or retirement policy. Buying costs such as property tax, conveyancing, surveys, valuation, moving costs and mortgage fees should be funded separately from the deposit unless a lender explicitly permits otherwise.

Only a lender or mortgage adviser can provide an assessment based on your full circumstances. An agreement in principle can still change after document checks, a full application and the lender’s property valuation.