HisabCalc

Mortgage Affordability

How large a mortgage your income supports, and which limit actually binds.

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Result

Figures are computed on your device; nothing is sent anywhere.

Formula

loan = min(income × multiple, payment the income share supports)

How the calculation works

A lender does not simply multiply your income. It applies two limits at once and the smaller one decides: a multiple of annual income, and a cap on how much of your monthly income the payment may take. Here the income multiple binds, giving 270,000, while the payment cap would have allowed 271,612. The gap is small, but which one binds changes what you should do next.

That is the practical value of showing both. When the payment share binds, the constraint is month-to-month affordability, and a larger deposit or a longer term changes the outcome. When the income multiple binds, neither helps the loan figure at all. The only lever left is a bigger deposit, which raises the property price without raising the loan.

The deposit sits outside both limits. It is not borrowed, so it does not consume affordability, and it adds to the price you can pay rather than to the loan you can service. This is why the two figures are reported separately.

Common mistakes

When to use it

Worked example

On 60,000 a year with 20,000 saved at 6% over 25 years, the loan is 270,000 and the property 290,000.

Monthly income 5,000.00
Max payment 1,750.00
Loan by multiple 270,000.00
Loan by payment 271,612.01
Maximum loan 270,000.00
Max property price 290,000.00

Common questions

Why two limits?

Lenders apply a multiple of income and a cap on the payment share. Whichever binds first is the real limit.

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Last updated: 2026-09-29