When selling your home, the number of square meters of living space is perhaps the most important value determining factor for the market value and the final selling price. How to calculate it?

The “NEN2580” measuring instruction has been created to standardize all surface surveys of homes. Are you going to sell the property there are a number of areas that we look at and that are:

  • user area (all areas where you can walk around)
  • living space (the part of the use surface that is suitable for use as living/sleeping space)
  • other indoor space (think of the cold and/or dark storage room)
  • building-related outdoor space (balcony or roof terrace)
  • external storage space (think of the detached stone shed in your garden or your storage in the basement of the flat)
  • content of the house in cubic meters (m3)
  • size of the plot

The most important factors for the value of the home are: the living space, your outdoor space and the surface of the entire plot.

Step 1: calculate the usage surface
We assume a standard home. Your home has 4 exterior walls that close it off from the outside world.

Begin in the home by measuring the total area between those 4 walls. So from the inside wall between you and your left neighbour to the inside wall between you and your right neighbour.

Then from the inside outside wall at the front to the inside outside wall at the rear. Forget all the partitions, radiators, cable ducts, the stair cupboard, pipes, baseboards, support pillars (with a diameter of less than 50 cm) and so on. Also forget the space that is not directly attached to your home (your storage room in the garden or in the basement of your flat). You don’t have to take that into account. Simply straightforward to measure from wall to wall. Do this for every floor in your home.

If you come to the attic, pay attention: you cannot include all surfaces that are lower than 1.50 meters. Almost every attic has a sloping roof, so there is a part that does not count.

Stairs and any voids are important. For this applies that if larger than or equal to 4 m2, you may not count this in the user area. In most single-family homes, stairways will not be larger than 4 m2, so you do not have to take this into account.

The outcome of your admission is, for example, as follows:

Floor Width Length Surface
1st Floor 5 10 50 m2
2e Floor 5 10 50 m2
Attic 4 8 40 m2
Total: 140 m2

The total surface area of ​​your home is therefore 140 m2.

Step 2: calculate the remaining indoor space
You will then split the user area into living space and other indoor space.

To determine the remaining indoor space, go through the questions below. (No worries, below I give examples to these questions.)

  1. Is there space that is not suitable for construction or intended as living space? (Think of a storage room, garage, bicycle storage.) If yes: then note the area of ​​this space (s).
  2. Is the attic a storage attic? (An attic is a storage attic if there is no fixed staircase and/or no window of at least 0.5 m2 for daylight.) If so: note the area of ​​this attic but forget all area that is lower than 1.5 meters ( it does not count).
  3. Is there room in the home that is lower than 2 meters and higher than 1.5 meters? (In most cases this will also concern an attic or a loft.) If so: note the area of ​​all square meters that fall within it (1.5 and 2 meters).
  4. If you have a space that is at least 2 meters or higher, but the part of it that has that height is not at least 4 m2, then it does not count. (You will experience this, for example, in a high but small attic.) If the answer is yes, then also note this area.
  5. Do you have a basement? Is this at least 2 meters high and does it have no direct daylight? Then you do NOT have to include this in “other indoor space”. A basement may then simply count as living space, as long as it is also intended as such.

What this looks like in practice:

Question 1:
For example, you have a storage room that is clearly built and intended as a storage room. Here are bicycles, garden equipment etc.

Question 2:
For example, you have an attic that you can only reach with a Vlizotrap. Or you have an attic with a fixed staircase, but without a skylight of at least 0.5 m2. You then measure all the area of ​​that attic that is 1.50 meters and higher.

Question 3:
For example, you have an attic with a fixed staircase and a skylight of more than 0.5 m2. You have to note the surface of this attic that is between 1.50 and 2 meters high. Everything higher than 2 meters you do not have to do anything with it, that will come later when we calculate the living space.

Question 4:
You have the same attic as in the previous example. The attic is on the highest point 2.20 meters high. You are already calculating the area that is 2 meters and higher. The result is, for example, that you arrive at exactly 3.5 m2. Then you are unfortunately out of luck, because in order to be allowed to count as living space, a minimum of 4 m2 of that attic must be 2 meters or higher. That area then counts as “other indoor space”.

Add up all these areas and you have calculated the total indoor space of your home.

For instance

Storage space behind kitchen  8m2
Indoor garage 12m2
Part of the attic between 1.5 and 2m is 10m2
Total indoor space 20m2

Step 3 – calculate the living space
This is now very simple: take the surface of use from step 1 and subtract the surface of other indoor space from step 2. You have now calculated the living space of your home!

So in the case of the examples given, that is:

Usage area home                                         140m2

Other indoor space                                      20m2

Living area:                                                   120 m2

Calculate the building-related outdoor space
Please note: we are not talking about the garden here! You can measure the garden separately and state where you want it. When we talk about building-related outdoor space, we are talking about:

  • balconies
  • roof terraces
  • carports
  • verandas
  • terrace on the ground floor against the house that rests on a support is integrated in the building construction of the house

There is only talk of building-related outdoor space insofar as it is located next to, on, against or at the home.

Calculating this space needs no explanation. You measure exactly where the room runs (wall of the neighbours, or for example the eaves). The only exception is a covered outdoor area, which you measure up to the vertical vertical construction of this roof.

Calculate external storage space
The external storage space is:

  • storage in the basement of your apartment building
  • detached barn in the garden
  • garage box opposite your home

Please note: if the storage space is directly attached to your home, then it is a ‘other indoor space’, even if you cannot reach it from the inside. This is even so, if the storage space is a few meters away from your home, or shares one wall with your home. It looks like this:

Calculate the content of your home
To calculate the number of cubic meters of content in your home, look back at your calculation from step 1: the usage area. Take the area per floor and multiply it by the height of this floor. If there are height differences in the ceilings, you have to calculate the content per room.

Note: you must also include the dividing walls and partition walls with the content.

Angled surfaces and round surfaces are somewhat more difficult to calculate. It is now going too far to explain mathematical formulas for this that you can use to calculate it.

Calculate the plot of your home
We never calculate this, but it is always taken from the cadastral extract. Everyone can order this extract from his/her own home on the website of the Land Registry.