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Mortgage Lab tool

Flatmate/Boarder Income Calculator

See how boarder income could increase your borrowing power

Some lenders may consider flatmate or boarder income, but each lender decides how much it will accept and what evidence it needs. Use the shading input below as an illustrative scenario, not a lender policy.

Your Income

$
$

Boarder/Flatmate Income

$

Bank Assumptions

%

Illustrative assumption only; lender treatment varies.

%

Additional Borrowing Power

$37,185

With boarder income included

Without Boarder

$286,035

With Boarder

$323,220

Income Breakdown

Gross Boarder Income (Annual)$13,000
Shaded Amount (80%)$10,400
Monthly Boarder Income$1,083
Monthly (After Shading)$866

Important Notes

  • • Not all banks accept boarder income
  • • May need evidence of existing boarder arrangement
  • • Property must have suitable accommodation
  • • Flatmate or boarder payments may have tax implications; check how current IRD rules apply to your arrangement

How lenders usually treat boarder income

Flatmate or boarder income can help support a mortgage application, but banks usually do not count every dollar of it. Instead, they shade the income to allow for vacancies and uncertainty.

  • Some lenders accept it, while others are more conservative.
  • The income may need to fit within specific policy limits.
  • Evidence of the property setup or existing arrangement may be required.

Using this estimate the right way

This tool is best used to test scenarios before a real servicing assessment. It helps show whether boarder income could improve the application, but it is not a final lending decision.

  • Try different shading rates to reflect how lenders may view the income.
  • Use realistic weekly board and occupancy assumptions.
  • Pair the result with a full borrowing-power and deposit review.

Flatmate income FAQs

Do banks count flatmate or boarder income for a mortgage?

Some do, but usually not at 100%. Many lenders shade the income and may require the property to be suitable for a boarder arrangement.

Why do lenders shade boarder income?

Because there can be vacancy periods or uncertainty around whether the income will continue, so lenders often discount it for risk.

Can boarder income materially improve borrowing power?

It can, especially for first-home buyers on tighter servicing margins, but the impact depends on the lender, the shaded amount, and the rest of the application.

Disclaimer: This calculator provides estimates only and should not be relied upon for financial decisions. Actual loan terms, rates, and eligibility may vary. Please contact a Mortgage Lab adviser for personalised advice.

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