How Is the Fiscal Power of a Vehicle Calculated?

All owners of a vehicle that is duly registered in Spain, including motorcycle owners, are obliged to pay an annual road tax.

The amount to be paid for it depends on the so-called fiscal power, which is represented by the fiscal horses. This is a measurement that, contrary to what one might think, is not related to the power of the vehicle in CV (horsepower). However, these fiscal horses are taken into account by the State to determine the amount that an owner must pay for his vehicle.

What Is Fiscal Power And Fiscal Horses

Keep in mind that this amount must be paid by any owner of a vehicle in the country, for the simple fact of having it and that it is domiciled. This is the so-called Tax on Mechanical Traction Vehicles (IVTM).


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IVTM payment

Payment of the IVTM is made annually, and must be paid to the local authority. When a vehicle is purchased, the tax to be paid is calculated on a pro rata basis for the fiscal year; and if a car is not used for a whole year, it can be “temporarily deregistered” so as not to have to pay this tax.

You also have to have other details such as late payment, which is an increase as a surcharge depending on the time that has passed. Likewise, it is noteworthy to indicate that the rate of the Tax on Mechanical Traction Vehicles is set by the locality of residence within a range established by the Government. This leads to great differences between cities for the same vehicle.

The rate is determined based on the tax power, making cars with higher power pay a higher fee. For their part, hybrid or electric vehicles have a significant discount.

What is fiscal power and fiscal horses

The tax power was one of the first systems through which tax rates began to be implemented in some European countries such as Germany, the United Kingdom, Belgium, Italy or France. The classification of the fiscal horsepower is not calculated on the real potential of the vehicle’s engine, but rather according to a mathematical formula that takes into account the dimensions of the cylinder.

There are countries in which other techniques are used, but the main European countries do continue to use it. However, the tax power is not the same in the United Kingdom as it is in Switzerland, Germany.

The relationship between horsepower and tax

There is currently no relationship between horsepower and fiscal horsepower. This was not the case in the past, since when the vehicles did not have any supercharging, they had a small correlation between the two, meaning that the more powerful a car was, the more fiscal power it would have.

However, in reality the picture is very different and they are not related to each other. It all depends on the cylinders and the size of each of them. In fact, smaller motors that offer greater power have been increasingly advocated.

Where can you see the tax power of a vehicle

The fiscal power of the vehicle can be calculated according to the formula that we are going to indicate below, but you should know that you can also find it on the card of the Technical Vehicle Inspection of each car. Any vehicle that is registered in Spain must have this card and there is a section on it for fiscal power (CVF).

This information is usually located in the lower right part of the ITV file, being represented together with the power in kW, which is a unit used in physics.

Instructions for is the tax power of a vehicle calculated?

If you want to know how to calculate the fiscal power of your car, you must resort to the use of a mathematical formula. This is reflected in Royal Decree 2822/1998 of December 23, specifically in Annex V of the General Vehicle Regulations.

It establishes a formula by which it is possible to calculate the fiscal power, which is obtained from the number of cylinders and the displacement. This is the following:

f = T (0.785 D 2 R) 0.6 N

In this formula, f refers to the fiscal power; T is a factor that has a value of 0.11 in two-stroke engines and 0.08 in four-stroke engines; D refers to the diameter of the cylinder (in cm); R, the path of the piston, that is, its stroke (in cm); and N, which is the number of cylinders in the engine,

Similarly, if the size of the engine is known, which is calculated with the formula  C (cm 3) = N · V (C = displacement in cubic centimeters; N = number of cylinders; and V = cylinder volume), it is It is possible to use an alternative formula for calculating the tax power. This is the following:

f = T (C/N) 0.6 N