The calculation of cadastral spaces is a fundamental aspect for anyone who wants to buy or sell a property. This procedure, which allows to determine the cadastral income, directly influences the taxation of the property.

But what exactly are cadastral spaces and how are they calculated?

In the following article we will explore in detail the meaning of cadastral space and the methods of calculation, essential for those who wish to understand the real value of their home.

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## What are cadastral spaces?

The cadastral space represents the internal space of a property delimited by walls, with a minimum surface area of 9 m² and a maximum of 27 m². These spaces must receive natural light and are one of the main elements used in the calculation of the cadastral income. For surfaces greater than 27 m², the excess is calculated. The calculation of cadastral spaces is different depending on the property category and cadastral classification.

For example, dwellings generally belong to category “A”, while units intended for shops and warehouses fall into group “C”.

The concept of cadastral space varies according to the intended use of the property and its classification is established by the Land Registry, which uses different categories to determine the value and taxation.

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## Land registry income and real estate categories

There **cadastral income** is the economic value assigned to each property by the Land Registry and represents the potential income that the property can generate. This value is fundamental for determining taxes, such as IMU and **TASI**. The cadastral income varies according to the category of the property, which is determined by the characteristics of the building.

Properties are classified into three main categories **cadastral categories**:

**Group A**: concerns homes, private offices and historic buildings, where the useful space is the unit of measurement for the calculation.**Group B**: includes buildings with collective use, such as hospitals, schools and barracks. In this case, the volume of the property is used as the unit of measurement.**Group C**: includes shops, warehouses and storage premises, where the calculation is based on the surface area in square metres.

Each category has specific rules for calculating the cadastral consistency, which will determine the final income and, consequently, the taxes to be paid.

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## Calculation of cadastral consistency

The calculation of the **cadastral consistency** varies depending on the category to which the property belongs. For real estate units belonging to the **Group A**the calculation is based on the number of main and accessory rooms, applying specific rules:

**Main rooms**: They are counted by their actual number. For example, a bedroom or a kitchen fall into this category.**Direct accessory compartments**: These are spaces that directly serve the main rooms, such as bathrooms, corridors, entrances and storage rooms. These are counted as 1/3 of a room.**Indirect accessory compartments**: These include attics, cellars and other spaces that are accessed from outside the main rooms, and are calculated as 1/4 of a room.

Once all the rooms have been added together, you can add or subtract up to 10% to account for any property features that may affect the calculation. The final result is then rounded to the nearest half room.

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## Practical example of the calculation of cadastral spaces

Let’s now suppose we need to calculate the cadastral spaces of a house with the following characteristics:

- 1 living room of 35 m²
- 2 bedrooms of 20 m² each
- 1 bathroom of 8 m²
- 1 storage room of 5 m²
- 1 terrace of 50 m²

Here’s the procedure:

**Stay**: The living room has a surface area of 35 m², so it exceeds the threshold of 27 m². It is calculated as follows: 1 room + excess (35-27)/27 = 0.30. Total: 1.30 rooms.**Bedrooms**: The two rooms have a surface area of 20 m² each, so they are each counted as 1 room. Total: 2 rooms.**Bath**: The bathroom, being 8 m², is less than 9 m², so it is counted as 1/3 of a room. Total: 0.33 rooms.**Closet**: The storage room, of 5 m², is also counted as 1/4 of a room. Total: 0.25 rooms.**Terrace**: For the calculation of the terrace, a percentage is considered. In this case, the value to be added is 10% of the previously calculated total.

Let’s add the rooms: 1.30 (living room) + 2 (bedrooms) + 0.33 (bathroom) + 0.25 (storage room) = **3.88 rooms**which rounded becomes **4 rooms**.

Now, let’s calculate the terrace contribution: 10% of 4 rooms is 0.40, which is rounded to 0.50 rooms.

So, the final total will be **4.5 rooms**.

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## Conclusion

The calculation of cadastral spaces is essential to correctly determine the cadastral income and, consequently, the taxes related to real estate. Understanding how the main and accessory spaces are calculated, as well as any excesses and additional percentages, allows you to have a clearer vision of the cadastral value of your property.

Whether you are buying or selling a home, knowing this information can be essential to making more informed choices, avoiding unpleasant surprises related to taxation.