Floor, usable and countable area of a flat: how to compare floor size

The figure given as the "area of a flat" has no single meaning. Different sellers and projects state the floor area, the usable area or the countable area, and each is calculated differently. Comparing flats by a single number can therefore lead to a wrong conclusion. Before comparing, you need to find out which type of area is stated for each flat and what it includes.

Why the figures differ for similar flats

Two flats with the same layout can have different floor sizes in their listings. The difference does not necessarily mean that one of them is larger. It often arises because each seller uses a different measuring method or includes different parts in the area: a balcony, loggia, terrace, cellar or hallway.

For a buyer, it is important to distinguish whether the area is stated only for the living spaces themselves, or including ancillary spaces. It is also worth knowing whether the figure comes from the design documentation or is a measured actual value after the building has been completed.

Three basic terms

Floor area

Floor area is the simple sum of the areas of all rooms in the flat, measured along the floor. It is usually measured around the perimeter of the rooms, that is, along the inner walls. It tells you how much space you actually have available in the flat. It may differ depending on whether the areas under partitions, shafts or service cores are included.

Usable area

Usable area is usually a narrower term than floor area. It generally includes the area of rooms that serve for living and for related functions of the flat, and anything not counted as usable is deducted from it. The exact definition may differ depending on the purpose for which the figure is used, for example for documentation, final approval of the building or sale. It is therefore always advisable to ask how it was determined in the specific case.

Countable area

Countable area is an area adjusted by coefficients according to the type of space. Outdoor spaces, such as balconies, loggias or terraces, are usually included in it only for part of their actual size. It is used mainly for developers' internal calculations, for allocating costs or for setting the price. For this reason, its value may be lower than the floor area of the whole flat including the outdoor parts.

What is and is not included in the area of a flat

When comparing, it is advisable to clarify for each offer how the following parts are treated:

• Balcony, loggia and terrace – sometimes they are stated separately, sometimes they are included in the total area, and sometimes only in part.
• Cellar and storage room – they may be part of the flat unit, or a separately sold or leased part.
• Sloping ceilings and attic – an area with low clear height is often counted only in part or not at all.
• Partitions, shafts and service cores – depending on the measuring method, the area under them may or may not be deducted.
• Garden and front garden – for ground-floor flats these are usually stated separately and do not form part of the flat's floor size.

How to compare flats properly

To make the comparison fair, follow a few steps:

1. For each flat, ask for a breakdown of areas by individual room, including the outdoor parts.
2. Find out which type of area the price per square metre refers to, and whether the price relates to the total area or only to the interior.
3. Compare the same type of area. If that is not possible, recalculate the figures yourself from the room breakdown.
4. Also assess how the space can actually be used: the shape of the rooms, passages, the position of the windows and the possibilities for placing furniture.
5. Do not forget that the price of the flat and the price of ancillary spaces may be stated separately.

You can supplement an approximate comparison with our calculator, into which you can enter the price and floor size to obtain a comparable price per square metre. You can browse new-build offers in the project catalogue or by location.

What to ask the seller and what to check in the contract

To be safe, have the following confirmed in writing:

• which type of area is stated in the offer and by what method it was determined,
• whether it is the area according to the design or the actual survey after completion,
• how the balcony, loggia, terrace and cellar are treated,
• whether the floor size may change after the building is completed and what effect this would have on the price,
• which figure will be stated in the purchase contract or the contract on a future contract.

If the price depends on the floor size, have the recalculation procedure explained and put in writing in case the area changes. We recommend consulting a lawyer about the contractual terms. If you are financing the flat with a mortgage, check with a mortgage specialist which area figure the bank uses when assessing the property. You will find general advice on buying in our buyer's guide.

A practical example of a comparison

Imagine two flats with a similar layout. The first offer states a single total area including the loggia. The second states the area of the interior rooms separately and the area of the outdoor space separately. Looking at the number alone, the first flat appears larger and its price per square metre more favourable. After recalculating to the same basis, that is, to the interior spaces only, it may turn out that the difference is smaller, or that the second offer is better value.

What you are comparing	What to watch out for
Total area	Whether it includes outdoor parts and ancillary spaces
Interior area	Whether it is measured along the walls or according to the design
Price per square metre	Which area the price refers to
Outdoor spaces	Whether they are counted in full, in part, or separately

If you are not sure how to read the floor size in a specific offer, you can send us a housing inquiry form. You can also find information about the companies that build the flats in the overview of developers.

Frequently asked questions

Is it better to compare flats by floor area or usable area?

What matters is that the same type of area is used for all the flats being compared. For an idea of the real living space, the interior area without outdoor parts is useful, but always supplement it with details of the balcony, loggia or cellar.

Can the floor size of a flat change after the building is completed?

Yes, the actual survey after completion may differ slightly from the design. It is therefore worth finding out in advance whether the price is tied to the area and how any difference is dealt with. We recommend having the provision checked by a lawyer.

Is a balcony or terrace also included in the price per square metre?

It depends on the seller. Sometimes the outdoor space is part of the area from which the price is calculated, and sometimes it is sold separately. Always ask for a breakdown of areas and check which basis the price refers to.