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How do I calculate the rebuild cost of my home?

When you get a home insurance quote, we'll estimate the rebuild cost of your home. But how do you work it out yourself?

From using a rebuild cost calculator, to working out the square metres of your house, here's what you need to know about calculating your rebuild costs.

The interior of a house that is being rebuilt


What is the rebuild cost of my house?

The rebuild cost of your house isn’t the amount you paid for it, or it’s current market value. Rather, it’s the amount of money you need to rebuild it from scratch if it was destroyed by a calamity such as a fire or flood.

This means your rebuild cost needs to take into account the price of labour where you live as well as the cost of materials. It should also include:

  • Survey costs
  • Plumbing
  • Electrics
  • Costs associated with the demolition and clearing of your old property. 

Why do I need to know the rebuild cost of my house ?

If your home was damaged beyond repair in a serious flood or fire your home insurance should cover the cost of building a new one. This is why your insurance company asks you for a rebuild figure when you get a home insurance policy.

It’s important this figure is accurate to ensure that you have sufficient cover to ensure that your home can be rebuilt. Find out how to make sure you've got the right amount of insurance cover.

In England, government figures reveal more than 60,000 dwellings were damaged by fire in 2021. Likewise, around 5 million people live in flood-risk areas. When houses are seriously flooded, the damage might be beyond repair. 

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Why does the house rebuild cost differ from the market value?

The actual cost to rebuild a house is usually below its market value. In other words, it’s less than the amount you might get if you sold it. This is because these factors are likely to have a significant bearing on the amount somebody is prepared to pay for your house:

  • The land it sits on
  • Its location
  • Nearby school catchment areas

Clearly there’s not any one-size-fits-all answer to the question of how much it costs to rebuild your home from the foundations up - different types of property cost different amounts to rebuild.

For example, a terraced house might come in at a different price from a detached one. Home improvements, such as a loft conversion, could also add to the cost.

Age plays a role in the cost too, with ornate Victorian properties costing more to rebuild than modern pads. And if you live in a listed building, there are extra costs to ensure any rebuilding work is done with period appropriate tools and techniques.


How much will it cost to rebuild my house?

You could get a rough idea about how much it would cost to rebuild your home from:

  • The deeds to your home
  • Your mortgage valuation report
  • Your buildings insurance renewal policy documents
  • The surveyor’s report when you bought the place

However, these might be out of date, so to err on the side of caution it might make sense to use get a new rebuild figure. 

How to work out the rebuild cost for insurance
There are 2 methods you can use to calculator your home's rebuild cost. They vary in price and complexity, depending on your circumstances:
  • Use a rebuild cost calculator
  • Hire a surveyor to work it out for you

If you want to use a rebuild cost calculator, you need to work out the size of your property in square metres. 

If you decide to use a surveyor, it might costs around £250 to get an assessment of your home's rebuild cost.


Is there a rebuild cost calculator?

You could use the Royal Institute of Chartered Surveyors (RICS) Building Cost Information Service (BCIS).

This should provide a rough estimate of the rebuild costs based on information you type into the BCIS calculator.

You need to register to use the rebuild cost calculator, but it’s free, and draws on years of expertise from RICS members.

The calculator asks you for details about your house such as:

  • Your property type
  • The approximate age of your home
  • The number of rooms
  • The type of roof and walls
  • The external floor area (you can put this in as square feet or square metres)

Can I hire a surveyor to calculate the rebuild cost? 

You could use a chartered surveyor specialising in rebuild costs. This could cost a few hundred pounds, but the surveyor’s assessment should be as accurate as you can get.

This is because the surveyor visits your home in the process of drawing up the report and calculating the rebuild cost.

A surveyor is especially important if you’ve got a non-standard property, such as one with a thatched roof. Or if a large portion is made from timber or another less-common material. 

These, and historical or listed buildings aren’t covered by the RICS rebuild calculator.


What’s the average rebuild cost of a house? 

A key driver of your rebuild cost is the size of your house. 

According to NimbleFins, the average cost of rebuilding a 3-bed semi-detached home in the UK is now around £243,000. This is an increase of 17% compared to 2020. 

Bigger houses naturally cost more to rebuild than smaller ones. But it doesn’t necessarily follow that the cost to rebuild a house that’s 2000 square feet is double that of one that’s 1000 square feet. This is particularly true in houses with multiple stories as there’d still be only a single roof and one foundation.

Take the example of St Austell in Cornwall. A home that measures 1,000 square feet would have a rebuild cost of £196,000, according to Nimblefins. A 1,400 square feet house would cost £243,000 to rebuild, rising to £326,000 for a 2,000 square feet property.

However size isn’t the only factor to consider. There’s significant variation in regions across the UK, in particular as a result of differences in the costs of labour.


What’s the average rebuild cost of a house by region? 

Location Region Average rebuild cost
North East 
Yorkshire and Humber
West Midlands
East of England
East Midlands
North West
St Austell
South West
South East

*Based on a 1,400-square foot house, NimbleFins. Figures correct as of 1 August 2022.


How to measure your house in square metres

If you use the rebuild cost calculator, you need to know the size of your house.

This is because rebuilding cost calculators need to establish how many bricks and other materials would be required to rebuild it, and the length of drainage and pipe runs. If you use a chartered surveyor they should undertake the measuring-up task.

To give yourself an idea of the floor area of your home, do the following:

  • Go outside and measure the length and width of each of the ground floor walls.
  • Multiply each of your measurements together for the required ground floor total.
  • If the upstairs is identical to the downstairs, just double the ground-floor area.
  • If it isn’t, do your best to calculate the upstairs separately.
  • Look at any plans or deeds for the property if they’re to hand. Or measure the external walls from inside the property, adding the thickness of the external wall and any partition walls.
  • Add your first-floor measurement to that for the ground floor to get the total.

Armed with your calculation, you should be ready to use the rebuild cost calculator.

This should give you a rough guide on the rebuilding cost per square metre, and the total cost for your property.


How to calculate the rebuild cost of a flat or maisonette

You usually don’t need to buy buildings insurance if you live in a flat or maisonette - that’s normally the responsibility of your landlord.

But, as most flats are leasehold, a management company or building owner might already have buildings insurance in place.

While the freeholder should probably have paid for buildings insurance, some leaseholders club together and buy their own.

If you need to work out the rebuild cost, bear in mind that construction methods and materials are different for flats. For this reason, it’s usually best to let the surveyor do the work instead of using a rebuild cost calculator.


Will my rebuild cost change if I renovate my house?

If you make any structural changes to your house, such as a new extension or a loft conversion, the rebuild cost of your house is likely to go up.

This means it’s essential to tell your buildings insurance provider about any extensions or structural changes you make to your house. If you don’t you might end up under insured with a rebuild cost that’s too low. 

It’s likely that the cost of your buildings insurance could go up if you make major changes. But at least it gives you the peace of mind that if your home is ever damaged beyond repair, your policy should cover the full cost of rebuilding it.