What is your Sum Insured?

When you first take out house insurance with us, we’ll ask you to specify the total amount you would need to rebuild your home to the same quality – this is your Sum Insured. It’s the maximum amount to be paid, after any applicable excess, if your house was destroyed by a natural disaster or suffered significant damage from major events like flooding or fire. It not only needs to cover materials and labour, but other costs to rebuild your home like demolition, removal of debris, consents and other fees.

What Sum Insured is

  • The estimated maximum amount it would cost to repair or rebuild your home if it was destroyed, including retaining walls.
  • An amount that covers materials and labour as well as costs like demolition, removal of debris, consents and other fees.
  • An amount you need to choose.

What Sum Insured isn't

  • It's not the rateable value (RV) or capital value (CV) of your home.
  • It’s not the market value or the price you paid for your home.
  • It's not the value of the land.

Why an accurate Sum Insured is important

If your Sum Insured is too low, you may not be able to repair or rebuild your home to the same size and quality. You could also find yourself paying for some of the repairs or rebuild yourself. So, it’s really important to get it right.

Working out your Sum Insured.

The good news is the Cordell Sum Sure calculator is easy to use. All you need to do is enter your address and the calculator prepopulates itself with information about your property.

Your Sum Insured should include:

  • Fixtures and fittings (i.e. baths, toilets, ovens, heat pumps)
  • The floor area of your home
  • Fixed floor coverings (like carpet)
  • Demolition costs
  • Council consents and other professional fees
  • Labour costs
  • Land slope
  • Construction materials
  • Quality of materials and finish
  • Number of levels
  • Your home's design: villa, bungalow, contemporary and one-off architectural
  • Outbuildings such as detached garages and carports, granny flats
  • Driveways, decks, paths and fences.

Make sure you include recreational features (such as swimming pools and tennis courts) and retaining walls.

Ways to calculate your Sum Insured.

Use an online calculator

The Cordell Sum Sure calculator is free, easy-to-use and takes only a short time to complete. All you need to do is to enter your address in and it will generate an estimated cost for rebuilding your home. If the calculator pre-populates any incorrect information in its initial calculation, you can make changes manually so it provides a more realistic estimate for your home.

The figure is based on information gathered throughout New Zealand from third party organisations, such as your local council. The calculator takes into consideration anticipated construction costs, allowances for professional fees, demolition, removal of debris and GST.

Remember, the estimated figure produced by the calculator is a guide only. It also doesn’t take into consideration future changes to building costs (i.e. inflation) over your policy period so if you want to include an allowance for this in your Sum Insured, you’ll need to add it to the estimate generated by the calculator. The calculator will account for price difference in some of these services around New Zealand.


Calculate online.

Ask a professional

If you want more peace of mind that your Sum Insured is accurate, it may be useful for you to get a professional to assess your property. This is strongly recommended for large (>500sqm), high value (>$2m) or architecturally designed homes. QV and Construction Cost Consultants can provide residential valuations at a competitive price for Westpac customers. Contact them below: 

Alternatively find other registered professionals such as:

Cordell Sum Sure calculator – helpful information.

  • If your address can’t be found and it includes a unit number (e.g. 23a), try different variations (e.g. 1/23, 23/1).
  • If your address still can’t be found, Cordell Sum Sure calculator may not have details of the property, it may be a new subdivision or the calculator is not suitable for the property at that address.
  • Don't worry if the photograph doesn’t match your house. The photograph might be different (e.g. your house is brand new, or there is an old photo, a boundary photo or street front photo) but the property details are based on the address not the photo.
  • The calculator assumes an average floor area for any garages, sheds or pool houses, so if you have a particularly large detached building you might want to select a Sum Insured higher than the estimate the calculator provides.
  • If you’re in the Canterbury area and your property has been identified as having a CERA technical category rating (foundation requirements), then an allowance will have been made for this. This is indicative only and you should seek specific engineering advice for a reliable estimate of any costs.
  • The calculator uses typical building costs for standard finishes to provide an estimate. If your home has significant special features and fittings, was built to a superior standard, is very large or has a high value, consider using other options to establish a better estimate of the rebuilding cost, such as a registered property valuer or quantity surveyor, or select a Sum Insured higher than the estimate the calculator provides.
  • Factors such as the slope (steepness) of your land, the style and quality of construction are important to get right when using the calculator. Ask for advice if you’re unsure what to enter in the calculator.

Shared ownership

  • Owners of cross-leased properties need to consider how to cover shared assets such as driveways, fences and retaining walls. Check your property's Title documents for reference to a 'plan of flats' (or similar) that sets out the various areas the cross lease applies to, and if you're still unsure, talk to your legal advisor.
  • Body corporates must consider all the units in their multi-dwelling property as well as any common property.

Things you should know.

This calculator provides an estimate Sum Insured for your home but the final decision is yours, so if you think your amount is not correct you can change it. This is general information and is not a recommendation, opinion or guidance. If you would like a recommendation, please contact a registered valuer or quantity surveyor. This calculator information does not provide any advice or opinion on the extent or adequacy of the cover provided by Sum Insured insurance. This is general information and not financial advice and it does not take into account your particular situation. You must make your own decision on the Sum Insured that is appropriate for your circumstances.

The Cordell Sum Sure calculator is an independent tool. Westpac does not have access to the information you enter, or access to the estimate that it produces, so if you’d like to adjust your home’s Sum Insured, you’ll need to contact us. It’s your responsibility to ensure that your Sum Insured is adequate.

Access to the Cordell Sum Sure Calculator is provided for your assistance only. The Cordell Sum Sure calculator takes the answers you input (or confirm, as applicable) and analyses them against construction industry data collated by CoreLogic to generate an estimated reconstruction cost of the improvements on your property. Use of the Cordell Sum Sure calculator and any estimated reconstruction cost provided by it may not be appropriate for you and you will need to assess this given your knowledge of your property. A number of qualifications apply to the estimated reconstruction cost and a full set of these are contained in the terms relating to this website. Neither IAG New Zealand Limited (“IAG”) (or a relevant related company, as the case may be) nor Westpac Banking Corporation ABN 33 007 457 141 nor Westpac New Zealand Limited (“Westpac”) (or a relevant related company, as the case may be) take any responsibility for the estimated costs provided by CoreLogic nor any liability for the accuracy of or reliance upon or use of, the costs. Access to Cordell’s calculator is provided for your assistance only. Westpac accepts no responsibility for the availability of the Cordell Sum Sure calculator.