Debt Service Ratio Calculator NZ 2026

This calculator works out the Debt Service Ratio (DSR) for a New Zealand rental or commercial property investment, a figure lenders use to judge whether a property earns enough income to cover its debt costs. You enter two figures: the property's Net Operating Income (NOI), the income left after operating expenses but before debt payments, and its Annual Debt Service Cost (ADS), the total yearly cost of servicing the debt, including mortgage principal and interest, lease costs, rates and insurance. Press Calculate and the tool divides NOI by ADS to return your Debt Service Ratio as a single decimal figure. A ratio of 1.0 means the property's income exactly covers its debt costs. Anything below 1.0 means the property is not generating enough income to service its debt, which can limit your ability to raise further lending against it, while a ratio comfortably above 1.0 signals healthier serviceability and more borrowing headroom. Lenders typically want to see a DSR with some buffer above 1.0 before approving additional finance, so use this figure to gauge how a property stacks up before you apply, or to compare the debt serviceability of different investment properties. Update the NOI and ADS figures whenever your income or debt costs change, such as after a rent review or refinancing. This is an indicative estimate only, not financial or lending advice, and actual bank criteria vary.

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Enter your information into the calculator below, and push Calculate.