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House Insurance Calculator

With construction costs increasing, make sure your rebuild cost is fully insured - our guide explains everything you need to know.
​Updated 14 October 2023
Estimating the rebuild cost of your home is essential for house insurance policies
  • Insurers ask for a ‘sum insured’ which is the highest amount that will be paid out if a house is damaged beyond repair.
  • Insure for too low, and you could be out of pocket. Insure too high, and you are overpaying on your insurance policy.
  • Because sum insured is based on today's building costs, how much you paid for your house, its rateable value or current QV.co.nz estimate is irrelevant. 
  • House building costs generally increase every year due to inflation, and more so since 2020 per this RNZ article from 2022. This means you will need to make sure your sum insured is accurate. If you have recently renovated or extended, it's likely your sum insured value will need to be increased.

Related resources: Our trusted go-to guides for Insuring an Old House and Difficult Areas for House Insurance explain what you need to know should either of these issues apply to you.
Why calculate your home's rebuild cost?
  • If your house is damaged or destroyed, you need to make sure you have the right level of house insurance cover.
  • If you have too little, you won't be able to rebuild or repair your home without being out of pocket.
  • House insurance policies require you to estimate the cost of rebuilding your house, also known as the 'sum insured' value. This is maximum your insurer will pay out to repair or rebuild your home if it is damaged or destroyed.

How Much Should I Insure My House For?
In the video below, MoneyHub Founder Christopher Walsh explains how house insurance calculators work and why you must ensure you have enough coverage every time you renew or switch insurers:

Compare House Insurance Quotes With Our Top Insurers

  • Our research highlighted a shortlist of price and value-leading house insurers. We suggest getting quotes from Tower and Initio to get an idea of what it's going to cost, and comparing that with your existing insurer (if applicable). The more quotes from different providers the better - you'll know exactly what you should be paying.
  • Getting a quote is easy and fast - a couple of minutes is all you'll need to get two or three quotes.
  • Switching house insurers can save you money - the best insurers offer good deals year-round to attract new customers. 
  • For homeowners in the Wellington or Christchurch region, quotes are more difficult to obtain. Initio is the only insurer to offer upfront online quotes to every address in both cities, which makes the process of comparing a little bit easier.
  • ​​Advertising Disclaimer: MoneyHub may earn a referral bonus for anyone that’s approved through any link.

House Insurance Calculator - Frequently Asked Questions

We have listed popular FAQs to help you understand the importance of 'sum insured' and why you need it to be accurate and reflective of your total rebuild cost.

Can my home insurer calculate my 'sum insured' or home replacement value?

No - it is the responsibility of the insurance policyholder to estimate their sum insured value. Every house is different, and for this reason, no insurer can estimate or provide direction for how much your house would cost to rebuild. 

Is the home insurance calculator accurate?

The online calculator is provided by ​​Cordell, New Zealand's leader in building replacement cost calculators. Cordell has a wealth of experience in overseas markets, and brings its technology to New Zealand, which is free to use.

The Cordell Sum Sure Calculator is used by thousands of people every year from all over New Zealand. While accuracy is at the heart of every calculation, the Cordell Online Sum Insured calculator does not consider every possible feature of a home. You are asked to specify any special features or additions your home has to make the quote more accurate. The true cost of replacing your home will depend on the specific details of your home.

Please note, the Cordell Online Calculator does not provide advice, it is merely an estimate, and you can choose to rely on it, or not.

What are the limitations of the house insurance calculator?

While the Cordell Online Calculator can estimate your sum insured, it won't be able to take into account 'special features' which can alter the cost of rebuilding. These include:
  • Added costs if your house is built on an uneven section or steep slope
  • High-end luxury fittings
  • Building consents for high-end properties
  • Added costs involved with building in unique locations

Be aware: if your sum insured does not cover all your potential costs, you could end up paying for them yourself.

Other than the online calculator, how else can I estimate my home's sum insured value?

Beyond the calculator linked on this page, you can also contact a builder, architect, quantity surveyor or a property valuer. Please be aware that you are not insuring for the value of the land, just the rebuilding costs. In cities like Auckland and Tauranga, and locations like Queenstown, where land prices are relatively higher than other cities in New Zealand, your sum insured may be as low as 60% of your property value. For example, a $1m home in Auckland may have a sum insured value of $550,000, due to the high value of the land.

7 things to consider when comparing home insurance policies

  1. Index-linked cover - building costs go up over time; does the covered amount increase with inflation to meet the predicted costs of rebuilding later on?
  2. Temporary and alternative accommodation - if you can't live in your home due to a fire, flood or earthquake etc, does the policy compensate you for the costs of finding another place to live (i.e. rental and bond costs).
  3. Excess - often overlooked, how much can you afford in cash if you need to make a claim? As a rule, the lower the excess, the higher the insurance cost. 
  4. Water damage - does your policy cover damage caused by burst pipes or accidental flooding?
  5. Home Emergency Services - some insurance policies include cover for heating and plumbing repairs along with other home emergencies as part of their standard policy. But others do not, or offer it as an optional extra.
  6. No claims discount - what will the premium cost when you renew if you don't make any claims?
  7. Different cover for different policies - our guide to home insurance indicates there is a range in benefits offered by home insurers. Make sure you understand where there are differences, and if they affect you.
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