Sum Insured vs Rebuild Cost Calculator NZ

This calculator checks whether your house sum insured is enough to cover the full cost of rebuilding your home in New Zealand, and shows any underinsurance shortfall. Since the move to sum-insured house policies around 2013, the figure you nominate is the absolute most your insurer will pay if your home is destroyed, which means the risk of setting it too low sits squarely with you. Underinsurance is widespread, partly because building costs have climbed steeply in recent years and many people have not updated a figure set long ago, and partly because rebuilding to current standards, including demolition, professional fees, and the cost of working on a sloped or hard-to-access site, costs far more than people assume. You enter your current sum insured and your best estimate of the full rebuild cost, ideally from a rebuild calculator or a professional assessment, and the calculator shows whether you are adequately covered, the dollar shortfall if you are underinsured, and the share of the rebuild your cover would actually fund. If there is a gap, it is a prompt to get a proper rebuild assessment and lift your sum insured, because discovering the shortfall after a disaster is the worst possible time.

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$
Underinsured by $100,000
based on your rebuild estimate
Rebuild covered85%
Shortfall$100,000

Rebuild cost should include demolition, professional fees and site factors. Get a professional rebuild assessment to be sure. Estimate only.

How it works

The calculator compares your sum insured with the rebuild cost. If the sum insured is lower, the shortfall is the difference, and the share covered is the sum insured divided by the rebuild cost. If your sum insured matches or exceeds the rebuild cost, you are adequately covered.

Worked example

A 550,000 dollar sum insured against a 650,000 dollar rebuild leaves a 100,000 dollar shortfall, covering about 85 percent of the rebuild. On a total loss you would need to find that 100,000 dollars yourself.

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Frequently asked questions

What is a sum-insured house policy?

Since around 2013, most New Zealand house insurance is sum insured, meaning you set a dollar figure that is the most the insurer will pay to rebuild. If that figure is too low, you carry the shortfall yourself.

How do I know my rebuild cost?

Use a rebuild calculator that accounts for your home's size, materials, slope and location, or get a professional rebuild assessment. Building costs have risen sharply, so an old figure is often well short.

What happens if I am underinsured?

On a total loss the insurer pays only up to your sum insured, and you must fund the rest of the rebuild. Even partial claims can be reduced if your sum insured is far below the true rebuild cost.