Estimate
Fiscal horsepower calculator
Estimate a vehicle's French fiscal horsepower (CV, box P.6) from its engine power — in kW or metric horsepower — according to its registration regime. Combustion and hybrid vehicles (electric out of scope).
Indicative estimate, rounded up — not tax advice. The official value is the one in box P.6 of the registration certificate. The full registration-certificate cost is obtained by multiplying the CV by the regional rate per fiscal horsepower (rates set yearly by each French region).
What is fiscal horsepower?
Fiscal horsepower (CV) is a vehicle's administrative power unit, shown in box P.6 of the French registration certificate. It does not measure the engine's real power (expressed in kW or DIN hp): it is a computed value used by the administration to set certain taxes.
Not to be confused: metric horsepower (hp, DIN) measures real mechanical power (1 hp = 0.7355 kW), whereas fiscal horsepower (CV) is a purely administrative figure derived from power — and, for older vehicles, from CO₂ emissions.
How is fiscal horsepower computed?
For a vehicle registered since 1 January 2020, fiscal horsepower depends only on engine power in kW:
CV = 1,34 + 1,8 × (kW / 100)² + 3,87 × (kW / 100)
For a combustion vehicle registered before 2020, it combines CO₂ emissions (box V.7, in g/km) and power in kW:
CV = (CO₂ / 45) + (kW / 40)^1,6
The result is rounded up (7.01 becomes 8 CV). Electric vehicles fall under specific rules not covered by this calculator.
What is fiscal horsepower used for?
Fiscal horsepower is primarily the basis of the French registration certificate (carte grise) cost: each region sets the rate per fiscal horsepower, and the regional tax equals the number of CV multiplied by that rate.
It also feeds other administrative scales, such as mileage allowances or some insurance premiums. Knowing a vehicle's CV therefore helps anticipate the registration budget before a purchase or a transfer.