Tools & FAQs

How to measure the floor area of your house

Establishing the correct square metre floor area of your home will usually be required to help you work out a sum insured amount. It's important this is as accurate as possible, as it can be a key part of working out your home's total rebuild costs. This method can also be used to work out the size of your driveway and deck when using the house insurance calculator.

How to work out the area of your house

Before you get out the tape measure, there may be some easier ways to find out what the floor area of your house might be. Try looking in the first instance at:

  • your local council website
  • builder or architect plans
  • previous valuations
  • online property valuation sites.

Note: Be careful when using any of the above resources. Existing figures may not always be accurate, i.e. recent renovations may not be accounted for. So, you'll still want to follow through with a few measurements to double-check your floor area is correct.

If you do need to measure your floor area manually, it's best to measure the external walls. And don't forget any upper stories, detached buildings or garages.

Once you have basic measurements, the square metre area is calculated by multiplying the length of your home by the width. Depending on the shape of your layout, you may like to break this down into sections.

As you can see in the example, we've broken a home with a garage into two sections. The house measures 9 metres by 12 metres, giving us 108 square metres. The garage is 6 metres by 3 metres, which equals 18 square metres. Adding the two together, we reach the total floor area of 126 square metres.

Measuring the square meter floor area of your home.

Or hire a professional

Another way to determine your floor area is to use the services of a builder, architect or quantity surveyor. Though, as you'd expect, you'll probably have to pay for these services.

Updating your sum insured

Remember, once you have your measurements and new sum insured, please contact your insurer to update them.

A bit of a disaster

The Smith family’s Christchurch home was badly damaged in the Canterbury earthquake. Unfortunately, the Smiths had not correctly measured the large extension to their home, so they set a sum insured based on a home two-thirds its actual size. As a result, their insurance company was only required to cover the cost of rebuilding a standard 100sqm house – not their 160sqm dream home which would have required a much higher sum insured. Worse still, a mortgage of $250,000 on a rebuilt house worth only $180,000 saw the Smiths left with negative equity on their property.

This highlights the importance of taking the time to ensure you have the right level of cover in place.

For illustrative purposes only. To be used as a guide.

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