Joint Income Affordability Calculator
Estimate the mortgage two incomes support using an income multiple, adjusted for existing debts, and the property price the deposit then reaches.
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Most lenders start from an income multiple — commonly four to four and a half times combined gross income — and reduce it for existing commitments. Understanding that starting point tells you which properties are realistic before you spend weekends viewing ones that are not.
It is a starting point rather than an answer. Lenders then run a full affordability assessment, stress-test the payment at a higher rate, and can lend more or less than the multiple suggests depending on income type and outgoings.
The calculation
Combined income × the multiple gives the headline borrowing. Existing monthly commitments are annualised and multiplied by the same factor, then deducted, because a lender treats committed spending as income that is not available for a mortgage.
Worked example
Incomes of 55,000 and 38,000 total 93,000. At 4.5 times that is 418,500. Existing commitments of 400 a month are 4,800 a year, which at the same multiple removes 21,600, leaving 396,900. With a 60,000 deposit the property budget is about 456,900, and the payment at 6.5% over 25 years is around 2,680 a month.
Clearing a small debt can be worth a lot
On a 4.5 multiple, every 100 of monthly commitment costs 5,400 of borrowing. Clearing a car loan before applying frequently unlocks more borrowing than the loan balance itself, which is why it is worth doing several months in advance.
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Create your free property pageFrequently asked questions
What income multiple do lenders use?
Typically four to four and a half times combined gross income, with some lending more for higher incomes or certain professions. It is a cap rather than a promise — the affordability assessment can still produce a lower figure.
Are both incomes counted equally?
Usually yes for basic salary. Bonus, commission, overtime and self-employed income are often counted at a reduced rate or averaged over two to three years, so a variable income supports less borrowing than its headline suggests.
Does clearing debt before applying help?
Considerably. Each 100 of monthly commitment removed adds several thousand of borrowing at typical multiples. Clear balances a few months ahead so the improvement is visible on your credit file when you apply.
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