BHP to kW Converter
Convert brake horsepower into the kilowatt figure that registration documents, insurers and European tax offices actually use — with a PS cross-check so you know which number you started with.
Converting brake horsepower to kilowatts is one multiplication. The part worth reading is the sanity check underneath it: a large share of "bhp" figures floating around classified ads and forums were never bhp at all, and using the wrong one can push a car into a different insurance group or tax band.
BHP to kW Conversion Chart
The middle column is the honest conversion. The right-hand column shows what you would get if the source number was actually metric horsepower wearing a bhp label — worth glancing at whenever the input is a suspiciously round number.
| Figure quoted | kW if it is bhp | kW if it is really PS | Difference |
|---|---|---|---|
| 75 | 55.9 | 55.2 | 0.8 kW |
| 100 | 74.6 | 73.5 | 1.0 kW |
| 120 | 89.5 | 88.3 | 1.2 kW |
| 150 | 111.9 | 110.3 | 1.5 kW |
| 180 | 134.2 | 132.4 | 1.8 kW |
| 200 | 149.1 | 147.1 | 2.0 kW |
| 250 | 186.4 | 183.9 | 2.6 kW |
| 300 | 223.7 | 220.6 | 3.1 kW |
| 350 | 261.0 | 257.4 | 3.6 kW |
| 400 | 298.3 | 294.2 | 4.1 kW |
| 450 | 335.6 | 331.0 | 4.6 kW |
| 500 | 372.8 | 367.7 | 5.1 kW |
| 600 | 447.4 | 441.3 | 6.1 kW |
| 700 | 522.0 | 514.8 | 7.1 kW |
| 1000 | 745.7 | 735.5 | 10.2 kW |
Is Your Number Really Brake Horsepower?
Three quick tests before you trust the conversion:
- Is it a round marketing number? 90, 150, 200, 245, 310, 420, 510 are PS steps. Manufacturers pick round PS values, not round bhp values, so a "310 bhp" German sedan is almost always 310 PS = 306 bhp = 228 kW.
- Where did it come from? A UK road test, an SAE-certified US figure or a manufacturer's UK press pack is genuine bhp. A continental brochure, a Japanese or Korean spec sheet, or a forum post copying a badge is PS.
- Was it measured at the wheels? Rolling-road numbers are wheel horsepower, not brake horsepower. Converting 250 whp to kW gives you 186 kW at the wheels, which isn't comparable to a registration document. Run it through whp to hp first.
If the source turns out to be metric, use the HP to kW converter in PS mode or read hp vs bhp vs PS vs kW for the full comparison.
The kW Thresholds That Cost Money
Most converters stop at the arithmetic. In practice the reason people convert bhp to kW is that a threshold somewhere is priced in kilowatts, and being a couple of kW over a line is expensive.
| Country | What is priced in kW | Where the line sits |
|---|---|---|
| Italy | Superbollo annual surtax | Charged on every kW above 185 kW (≈248 bhp), at €20 per excess kW for cars under five years old, tapering with vehicle age. |
| Austria | Motorbezogene Versicherungssteuer | Monthly charge based on (kW − allowance) plus a CO₂ component; the kW allowance shrinks each year, so the same car costs more when newly registered later. |
| France | Chevaux fiscaux (CV) | Registration certificate cost is priced per fiscal horsepower, and the modern CV formula is driven by kW and CO₂ rather than displacement. |
| UK & Ireland | Insurance rating | Underwriting systems key off the V5C kW value in field P.2, which is why two cars both advertised as "200 bhp" can quote differently. |
| Croatia, Serbia, Poland | Local registration & excise scales | Several bands are set in kW or in metric horsepower converted from kW, not in bhp. |
Rates and thresholds are set nationally and change with each budget, so treat the figures above as the shape of the rule rather than a current quotation, and confirm with the relevant tax authority before you commit to a purchase.
Beyond Cars: Motors, Generators and Pumps
Outside the automotive world the same 0.7457 factor converts nameplate horsepower into kilowatts, but two cautions apply.
Electric motors quote output, not input
A 10 hp motor produces 7.46 kW of shaft power. Its electrical draw is higher, because efficiency and power factor sit between the wall and the shaft — usually 8.3 to 8.8 kW input for a modern premium-efficiency machine. Sizing a supply from the shaft rating alone undersizes the circuit. The HP to kW three-phase calculator and motor full-load amps chart handle that properly.
Compressor and HVAC "HP" is a size code, not a power reading
A "1.5 HP" air conditioner isn't consuming 1.1 kW of shaft power — the label is a nominal capacity class. Converting it with 0.7457 gives a meaningless number. See aircon HP to watts for what those labels actually mean.
Related Conversions
For the reverse direction use the kW to bhp converter. If your figure is metric horsepower, kW to PS and bhp to PS cover it, and bhp to hp settles whether the two labels differ at all. The horsepower unit converter handles every unit in one box.
Frequently Asked Questions
One brake horsepower is 0.7457 kW. Exactly, 0.745699872 kW — because 1 bhp is defined as 550 ft·lbf/s.
149.1 kW. But if that 200 came off a badge it is really 200 PS, and the registration figure will read 147 kW.
Yes — bhp and mechanical hp are the same 745.6999 W unit, so both use 0.7457. Only PS differs, at 0.7355.
Registration documents, insurance rating tables and several national tax formulas all run on kilowatts. Italy surcharges every kW above 185; Austria prices its motor tax straight off the kW rating.
298.3 kW — about 113 kW over Italy's superbollo threshold, if you're registering the car there.
The unit maths is the same, but the result is wheel kilowatts. A rolling road has already lost 10–25% to the drivetrain, so it won't match a registration document.
Multiply by 1.34102209. So 150 kW × 1.341 = 201 bhp. Our kW to bhp converter does it directly.
Almost. The true value is 1.34102209. Rounding to 1.34 costs about 0.08% — under 1 bhp even on a 1,000 bhp engine.