Debt-to-income headroom calculator
Where a loan sits against the Reserve Bank's DTI thresholds, and how much room is left underneath.
When this comparison applies
RBNZ's DTI restrictions cover bank home lending, not non-bank lenders. This calculator does not assess exemptions; its threshold comparison is only for non-exempt lending.
Exemptions include Kāinga Ora loans; refinancing without increasing the original loan value; portability without increasing the loan; bridging finance; property remediation; and new-home construction or buying from the developer within six months of completion. Extending an existing home is not covered by the construction exemption. Confirm eligibility with your bank.
What to enter as existing debt
Use debt that counts for DTI, not a raw sum of balances. Include existing mortgages, student and car loans, and credit-card and overdraft limits rather than their drawn balances. Enter proposed new borrowing separately, without double counting.
RBNZ's examples exclude an interest-free family loan repayable only when the home is sold, bridging debt repaid on sale, and business debt. Do not exclude every family loan automatically; ask your bank to confirm debt treatment. The calculator simply adds the amounts you enter.
What the threshold actually restricts
The Reserve Bank does not forbid high-DTI lending. It limits how much of each bank's new lending may exceed the threshold, so a loan above it is possible but competes for a small allocation.
Your own bank's servicing test, which stresses the rate well above what you would pay today, can be the tighter constraint.