⚙️ Power Conversion Details
📊 Equivalence Specifications
How do you accurately convert kilowatts (kW) to metric horsepower (CV / PS) to compare electric, hybrid, and combustion engine outputs in Spain for 2026? According to the General Directorate of Traffic (DGT) and Royal Decree 2822/1998 on Spanish Vehicle Regulations, the official power of any registered car must legally be recorded in kilowatts (kW) on the technical inspection card (Ficha Técnica ITV). However, manufacturers and buyers continue to use metric horsepower (CV or PS) for vehicle specifications. Knowing the exact conversion factor (where 1 kW equals 1.35962 CV) helps you verify the true capability of an electric car before buying it. You can calculate purchase expenses with our Car Loan Calculator or check annual road taxes in the Road Tax Calculator based on your municipality.
🔍 Mathematical Formula for Power Unit Conversion
The conversion between kilowatts and metric horsepower relies on constants defined in the International System of Units:
- Converting Kilowatts (kW) to Metric Horsepower (CV): Multiply the power value in kilowatts by the metric horsepower conversion constant (1 kW ≈ 1.35962 CV):
Formula: Power (CV) = Power (kW) × 1.35962
- Converting Metric Horsepower (CV) to Kilowatts (kW): Multiply the horsepower rating by the inverse conversion constant (1 CV ≈ 0.735499 kW):
Formula: Power (kW) = Power (CV) × 0.735499
📝 Practical Worked Examples
Example 1: Determining commercial horsepower of a new electric car
Persona: Juan is examining the technical specs of a newly imported electric car with a rated capacity of 100 kW.
- Conversion: kW to CV.
- Input Value: 100 kW.
- Math: 100 × 1.35962 = 135.962 CV.
Example 2: Converting a standard combustion engine to kW
Persona: Sofía wants to register an older car whose commercial catalog lists a power output of 150 CV.
- Conversion: CV to kW.
- Input Value: 150 CV.
- Math: 150 × 0.735499 = 110.3248 kW.
⚠️ 3 Common Mistakes When Comparing Engine Power
- Confusing Metric Horsepower (CV/PS) with Mechanical Horsepower (HP): The British imperial HP (used in UK and US catalogs) is equivalent to 0.7457 kW, while the European metric CV (PS) is equivalent to 0.7355 kW. This terminology mix-up can lead to a discrepancy of up to 5 CV on premium models, impacting resale valuations.
- Ignoring the difference between maximum power and 30-minute power in EVs: Technical specifications for electric cars often list a “30-minute power” rating (the continuous power the motor can sustain without overheating), which is significantly lower than peak output. This rating is used by municipalities to calculate road taxes, affecting your bill by up to €80 per year.
- Calculating Fiscal Horsepower (CVF) using a direct kW-to-CV conversion: Fiscal Horsepower is an administrative unit used for calculating local road tax. It is computed via a complex formula using engine displacement and cylinder count for thermal engines, or by dividing maximum power in kW by 5.11 for electric vehicles. Do not multiply by 1.35 or you will calculate the wrong tax category.
📋 What This Means for You
Electric Vehicle Buyers
Always look for the maximum useful power expressed in kW. Multiplying this value by 1.35962 gives you the true horsepower rating, allowing you to make direct performance comparisons with petrol or diesel cars.
Taxpayers Paying Local Road Tax (IVTM)
Local vehicle taxes are calculated using Fiscal Horsepower (CVF), which is printed on your ITV technical sheet. Understanding the conversion constant prevents surprises when the municipality issues its annual tax demand.
Mobility Tip: If you are planning a road trip and want to estimate your travel fuel costs based on engine size and power, check our Trip Fuel Cost Calculator to budget your trip.
❓ Frequently Asked Questions (FAQ)
The kilowatt (kW) is the official metric unit for power within the International System of Units (SI) and is mandated by EU vehicle type-approval regulations. The Spanish DGT uses it on registration documents to maintain international metrology standards.
According to the General Vehicle Regulations, the fiscal horsepower for pure electric vehicles is calculated by dividing the maximum 30-minute power rating (in kW) by the constant 5.11. This leads to very low tax brackets for EVs.
CV (Metric Horsepower) is a decimal unit defined as the power required to lift 75 kilograms by one meter in one second. HP (Mechanical Horsepower) is an imperial unit defined as lifting 550 pounds by one foot in one second, making 1 HP roughly 1.4% stronger than 1 CV.
Yes, while the raw power output is mathematically comparable, electric motors deliver maximum torque instantly from zero RPM. This gives an electric vehicle of 136 CV much quicker initial acceleration than an equivalent petrol car.
Yes, insurance underwriters penalize high power-to-weight ratios due to higher risk statistics. A vehicle exceeding 110 kW (150 CV) will generally face a 20% surcharge on its annual insurance premium compared to a standard model.
Your vehicle's official power output is printed in kilowatts (kW) on the technical inspection document (Ficha Técnica de la ITV) under section P.2, next to the engine fuel type indication.