Work out the fiscal horsepower of a car or a motorbike
Enter the power in kilowatts, or the engine size for a two-wheeler: the tool returns the fiscal horsepower and the regional tax for the region you pick.
Estimated fiscal horsepower
7 CV
formula: 6.71, rounded
| 1.80 × (kW ÷ 100)² | 1.66 |
| 3.87 × (kW ÷ 100) | 3.72 |
| Constant | 1.34 |
| Regional tax Île-de-France, under 10 years | €482.65 |
| Rate per fiscal horsepower | €68.95 |
Formula for cars registered since 2021. For an older car, the value in box P.6 is what counts, and the one the ANTS uses.
Fiscal horsepower, written CV for “chevaux fiscaux”, is the administrative power rating France uses to price the regional tax on a registration certificate, or carte grise; it appears in box P.6. It has nothing to do with the horsepower in the brochure. For a car registered in France since 1 January 2021, the law derives it only from the engine’s maximum net power in kilowatts, box P.2: divide the kW by one hundred, take 1.80 times that number squared, add 3.87 times the number, add 1.34, and round to the nearest whole number. A 96 kW car, about 131 hp, scores 6.71, so 7 CV. For motorbikes and scooters, the rating follows engine size, in steps up to half a litre and by a formula above that. Older cars had their rating set under other rules. In every case the figure in box P.6 is the one that counts for the tax.
Checked by Radif Partners · Editorial policy · Method and sources
The formula for cars since 2021
Article L421-16 of the French tax code sets a passenger car’s administrative power from its maximum net power, PM, in kilowatts: PA = 1.80 × (PM/100)² + 3.87 × (PM/100) + 1.34. The result is rounded to the nearest whole number. CO₂ emissions no longer play any part.
| Power (P.2) | Equivalent | Formula result | Fiscal horsepower | Regional tax in Pays de la Loire |
|---|---|---|---|---|
| 55 kW | 75 hp | 4.01 | 4 CV | €204 |
| 74 kW | 101 hp | 5.19 | 5 CV | €255 |
| 96 kW | 131 hp | 6.71 | 7 CV | €357 |
| 110 kW | 150 hp | 7.78 | 8 CV | €408 |
| 150 kW | 204 hp | 11.20 | 11 CV | €561 |
| 230 kW | 313 hp | 19.76 | 20 CV | €1,020 |
Where each extra CV starts
Because the result is rounded, one or two kilowatts can push a car into the next rating, and each extra CV adds your region’s rate to the bill. The table gives the power ranges for the most common ratings, which helps when two versions of the same model are on offer.
| Fiscal horsepower | Net power | Metric horsepower |
|---|---|---|
| 4 CV | 46 to 63 kW | 63 to 86 hp |
| 5 CV | 64 to 78 kW | 87 to 106 hp |
| 6 CV | 79 to 93 kW | 107 to 126 hp |
| 7 CV | 94 to 106 kW | 128 to 144 hp |
| 8 CV | 107 to 119 kW | 146 to 162 hp |
| 9 CV | 120 to 131 kW | 163 to 178 hp |
| 10 CV | 132 to 142 kW | 180 to 193 hp |
| 11 CV | 143 to 153 kW | 194 to 208 hp |
Motorbikes, scooters and trikes: engine size
For a petrol two-wheeler or tricycle, article L421-17 ignores power and uses the engine capacity in box P.1.
| Engine size | Fiscal horsepower |
|---|---|
| up to 125 cc | 1 CV |
| 126 to 175 cc | 2 CV |
| 176 to 250 cc | 3 CV |
| 251 to 350 cc | 4 CV |
| 351 to 500 cc | 5 CV |
Above that, the rating is 5 CV plus 8 times the capacity above half a litre, in litres, rounded up. Some examples: 125 cc: 1 CV; 300 cc: 4 CV; 650 cc: 7 CV; 900 cc: 9 CV; 1,300 cc: 12 CV. Motorbikes pay half the regional rate, with no further cut at ten years; mopeds pay no regional tax at all.
Older cars and box P.6
For a car registered before 1 January 2021, the rating was set under other rules, and this tool does not recompute it. The figure printed in box P.6 is presumed correct and is what the administration charges on, including when you buy the car years later. For an imported vehicle, the rating is set at its first French registration; the estimate above lets you price the paperwork before you buy.
What the tool does
Pick car or two-wheeler. For a car, enter the kilowatts from box P.2: the tool shows the three terms of the formula, their sum and the rounding. For a motorbike, enter the engine size. The region you choose then gives the rate per CV and the matching regional tax. To compare that rate across France, see the fiscal horsepower rate by region.