Horsepower to Kilowatts (hp to kW)
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Horsepower-to-kilowatts conversions translate US-customary horsepower automotive-engine, industrial-motor, marine-engine, and EV-motor power figures into SI-canonical metric kW for EU-export marketing, EN 60034 industrial-motor regulatory primaries, EU vehicle-type-approval documentation, and continental European cross-references. A 300 hp US-domestic sports-car engine converts to 224 kW on the EU-export marketing; a 200 hp US-marine-engine rating converts to 149 kW on the EU-import marine-engine documentation; a 1020 hp Tesla Model S Plaid total-motor power converts to 760 kW for the EU-marketing materials. The factor is exact at 0.7457 kW per mechanical hp under the US-customary mechanical-horsepower definition.
How to convert Horsepower to Kilowatts
Formula
kW = hp × 0.7457
To convert mechanical horsepower (US-customary) to kilowatts, multiply the hp figure by 0.7457 — equivalently, divide by 1.341, the hp value of one kW. The factor is fixed by the mechanical-horsepower definition at 745.69987 W since the late-eighteenth-century James Watt definition. For mental math, "hp × 0.75" is essentially identical precision; "hp × 0.7" understates by 6%, useful only for very rough approximation. For EU-export automotive marketing, EN 60034 industrial-motor regulatory documentation, EU-import marine-engine documentation, and EU-receiving-market generator-set documentation, use the full 0.7457 multiplier. The conversion runs at every US-customary-hp source to metric-kW destination boundary in cross-Atlantic engineering and export-marketing work, with the hp-figure on the US-customary side and the kW-figure on the EU-receiving-market regulatory documentation.
Worked examples
Example 1 — 1 hp
One mechanical horsepower (US-customary) equals exactly 0.7457 kW (specifically 745.69987 W) by SI definition. The factor is the reciprocal of the kW-to-hp factor of 1.341.
Example 2 — 200 hp
Two hundred mechanical horsepower — a typical US-light-truck engine rating — converts to 200 × 0.7457 = 149.1 kW, typically rounded to 149 kW on EU-export marketing materials. That is the figure on the EU regulatory-primary spec for the US-export light truck.
Example 3 — 1020 hp
One thousand and twenty mechanical horsepower — the Tesla Model S Plaid peak motor power — converts to 1020 × 0.7457 = 760.6 kW, typically rounded to 760 kW on EU-marketing materials. The conversion runs at every Tesla EU-marketing translation step.
hp to kW conversion table
| hp | kW |
|---|---|
| 1 hp | 0.7457 kW |
| 2 hp | 1.4914 kW |
| 3 hp | 2.2371 kW |
| 4 hp | 2.9828 kW |
| 5 hp | 3.7285 kW |
| 6 hp | 4.4742 kW |
| 7 hp | 5.2199 kW |
| 8 hp | 5.9656 kW |
| 9 hp | 6.7113 kW |
| 10 hp | 7.457 kW |
| 15 hp | 11.1855 kW |
| 20 hp | 14.914 kW |
| 25 hp | 18.6425 kW |
| 30 hp | 22.371 kW |
| 40 hp | 29.828 kW |
| 50 hp | 37.285 kW |
| 75 hp | 55.9275 kW |
| 100 hp | 74.57 kW |
| 150 hp | 111.855 kW |
| 200 hp | 149.14 kW |
| 250 hp | 186.425 kW |
| 500 hp | 372.8499 kW |
| 750 hp | 559.2749 kW |
| 1000 hp | 745.6999 kW |
| 2500 hp | 1864.2497 kW |
| 5000 hp | 3728.4994 kW |
Common hp to kW conversions
- 1 hp=0.7457 kW
- 50 hp=37.285 kW
- 100 hp=74.57 kW
- 150 hp=111.855 kW
- 200 hp=149.14 kW
- 300 hp=223.71 kW
- 500 hp=372.8499 kW
- 700 hp=521.9899 kW
- 1000 hp=745.6999 kW
- 2000 hp=1491.3997 kW
What is a Horsepower?
The horsepower (hp) under the US-customary mechanical-horsepower definition is exactly 745.69987158227022 W (typically rounded to 745.7 W). The metric horsepower (PS, sometimes "hp" in continental European contexts) is exactly 735.49875 W — about 1.4% smaller than the mechanical hp. The recognised symbols are "hp" (mechanical, US-customary) and "PS" or "ch" (metric, continental European), with both widely used and the disambiguation context-dependent. The horsepower is not part of the SI but is recognised by NIST as a US-customary power unit accepted for limited use, with ISO 80000-6 deprecating it in favour of kilowatts for new technical writing. The horsepower persists in US-customary automotive engine specs (every US-domestic car, truck, and motorcycle specifies engine power in hp), continental European automotive specs in PS for the consumer-recognition reference alongside kW regulatory primary, and a number of US-customary industrial-engineering legacy contexts.
The horsepower was defined by James Watt around 1782 to market his improved steam engines against the existing horse-powered industrial machinery they replaced. Watt observed that draft horses lifting coal from a Cornish mine could sustain about 22,000 foot-pounds per minute over a working day, rounded up to 33,000 foot-pounds per minute (550 foot-pounds per second) as the convenient marketing-friendly figure that would let buyers compare steam-engine output directly against horse-team capacity. The unit became the dominant power-rating convention for steam engines, internal-combustion engines, and US-customary engineering work through the nineteenth and twentieth centuries. Multiple slightly-different "horsepower" definitions emerged: the mechanical horsepower (US-imperial) at exactly 745.7 W, the metric horsepower (PS, "Pferdestärke" in German) at exactly 735.49875 W, the boiler horsepower (US-engineering) at 9809.5 W, and the electrical horsepower at 746 W (approximately equal to mechanical hp). The "hp" symbol typically refers to the mechanical horsepower in US contexts and the metric horsepower in continental European automotive specs. ISO 80000-6 deprecates horsepower in favour of kilowatts for new technical writing, but US-customary automotive and industrial-engine specs preserve it.
US-customary automotive engine power specs: every US-domestic car, truck, motorcycle, and ATV specifies engine power in horsepower on the manufacturer-spec sheet, advertising materials, and EPA-fuel-economy disclosures. Typical US passenger-car engine 150-300 hp; typical US light-truck 250-400 hp; typical US sports-car 400-700 hp; supercars 700-1000 hp. The horsepower-rating is the primary consumer-comparison metric for US-customary automotive marketing. Continental European automotive PS specs: European-manufactured cars (Volkswagen, BMW, Mercedes-Benz, Porsche, Ferrari, Lamborghini) preserve the metric horsepower (PS) on European-domestic-market spec sheets alongside kW as the regulatory primary under EU vehicle-type-approval rules. A "200 PS" Volkswagen Golf equates to 147 kW or 197 mechanical hp, with the PS-figure as the consumer-recognition reference and the kW-figure as the regulatory primary. US-customary industrial engines and pumps: US-customary industrial engine specs (Caterpillar diesel engines, Cummins generator sets, John Deere agricultural-equipment engines) and industrial pump specs (Goulds Pumps, Grundfos US-distribution) denominate rated power in horsepower for the US-customary engineering primary. A "200 hp diesel engine" delivers 149 kW of rated mechanical output. US-customary boating and small-craft motors: outboard-motor and stern-drive marine engines (Mercury Marine, Yamaha Marine, Honda Marine, Suzuki Marine) specify rated power in horsepower for the US-customary boat-and-small-craft engine sales. A 200 hp outboard motor delivers 149 kW of rated power.
What is a Kilowatt?
The kilowatt (kW) is exactly 1000 watts by SI prefix definition. The relationship is fixed and exact, with the kilo- prefix denoting 1000 of the underlying unit. One kW equals 1000 J/s of energy delivery, or 1000 W of power output, or 3.6 MJ delivered per hour (the basis of the kWh energy-billing unit). The recognised SI symbol is "kW", with lowercase "k" SI prefix and uppercase "W" honouring James Watt. The kilowatt is the standard everyday-engineering power unit for the typical residential-and-small-commercial range: kitchen appliances at 1-3 kW, residential solar-PV inverters at 3-10 kW, EV-charging Level-2 home-chargers at 7-11 kW, EV DC fast-chargers at 50-350 kW. Higher-power ranges use megawatts (MW, 1000 kW) for grid-scale power-generation and industrial loads, and gigawatts (GW, 1,000,000 kW) for nuclear-power stations and national-grid power-supply statistics.
The kilowatt emerged with the watt itself, fixed by the SI prefix system that has been in continuous use since the 1875 Metre Convention and incorporated into the SI at the 11th CGPM in 1960. Where the watt is small enough that everyday-engineering, consumer-electronics, and large-system power figures would land in awkward four-and-five-digit watt values, the kilowatt provides the more legible everyday-scale unit. The kW became dominant for residential and small-commercial electrical-power applications globally — every domestic appliance over about 1 kW, every residential solar-PV inverter, every EV charging system, every small wind turbine, and every industrial pneumatic-or-hydraulic system uses kW for the rated-power specification. The unit's adoption accelerated through the 1960s-1980s metrication transitions across continental Europe, Asia, Australia and Latin America, with kW replacing horsepower as the dominant power-rating unit on every metric-jurisdiction electrical and mechanical equipment specification. ISO 80000-6 specifies kW alongside W as the primary SI power unit for consumer-product and industrial-equipment ratings.
Residential electrical loads above 1 kW: every kitchen appliance over the dishwasher-and-microwave threshold (typical 1-3 kW), every residential air-conditioning system (typical 3-15 kW), every EV charging system (Level-2 home charging at 7-11 kW), every residential solar-PV inverter (3-10 kW typical), every residential wind turbine (1-10 kW). Consumer-facing product-rating labels on every EU-jurisdiction kitchen appliance display kW under EU Ecodesign Directive 2009/125/EC. Industrial electrical and mechanical equipment: industrial-pneumatic compressors (5-50 kW typical), industrial-hydraulic pump units (10-100 kW), industrial heat pumps (5-500 kW), commercial-HVAC systems (10-1000 kW), industrial electric-motor ratings (under European EN 60034 standards). Every industrial electrical-or-mechanical equipment manufacturer's spec sheet lists rated power in kW. EV battery systems: every electric-vehicle traction-battery system specifies usable-energy capacity in kWh and rated charging-power in kW. Tesla Model 3 Long Range at 75 kWh battery, 250 kW DC fast-charge peak; Nissan Leaf at 40 kWh battery, 50 kW DC fast-charge; Hyundai Ioniq 5 at 77 kWh battery, 220 kW DC fast-charge. Renewable-energy generation: residential solar-PV systems (3-10 kW peak rated capacity), small wind turbines (1-10 kW), commercial-rooftop solar arrays (50-500 kW), utility-scale solar farms (10-500 MW with each MW = 1000 kW).
Real-world uses for Horsepower to Kilowatts
US-customary hp automotive engine ratings translated to EU-export kW regulatory primary
US-manufactured automotive engines (Ford F-150, Chevrolet Corvette, Dodge Challenger, Tesla Model 3, Cadillac CT5-V) export to EU markets with mechanical-horsepower ratings translated to kW for the EU regulatory primary under EU vehicle-type-approval rules. A 300 hp Ford F-150 V6 translates to 224 kW; a 670 hp Dodge Challenger SRT Hellcat translates to 500 kW; a 1020 hp Tesla Model S Plaid translates to 760 kW. The conversion runs at every US-export car EU-marketing translation step.
US-customary hp industrial-motor ratings translated to EN 60034 EU-export kW
US-customary industrial-motor manufacturers (Baldor, GE Motors, Marathon Electric, US Motors) export to EU markets with mechanical-horsepower ratings translated to kW for the EN 60034 EU regulatory primary. A 100 hp industrial-pump motor translates to 75 kW on the EN 60034 spec; a 250 hp industrial-fan motor translates to 186 kW. The conversion runs at every US-export industrial-motor EU-receiving-market documentation step.
US-customary hp marine-engine ratings translated to kW EU-export marine-engine documentation
US-manufactured marine engines (Mercury Marine, Yamaha Marine US-distribution, Honda Marine US-distribution) export to EU markets with horsepower ratings translated to kW for the EU regulatory marine-engine documentation. A 200 hp outboard motor translates to 149 kW; a 300 hp stern-drive translates to 224 kW. The conversion runs at every US-marine-engine EU-export documentation step, with the hp-figure on the US-domestic spec and the kW-figure on the EU-receiving-market regulatory documentation.
US-customary hp generator-set ratings translated to kW EU-receiving-market documentation
US-customary generator-set manufacturers (Cummins Power Generation, Generac, Kohler Power Systems, Caterpillar Generator Sets, MTU Onsite Energy) export to EU markets with mechanical-horsepower ratings translated to kW for the EU-receiving-market regulatory documentation under EU EcoDesign and Stage-V emissions regulations. A 200 hp diesel-generator translates to 149 kW; a 500 hp natural-gas-generator translates to 373 kW; a 1000 hp prime-power genset translates to 745 kW. The conversion runs at every US-generator-set EU-export documentation step.
When to use Kilowatts instead of Horsepower
Use kilowatts whenever the destination is an EU regulatory-primary spec, EU vehicle-type-approval documentation, EN 60034 industrial-motor primary, EU-import marine-engine documentation, EU-export generator-set documentation, scientific or engineering publication, or any document where SI-canonical kW is the engineering-or-regulatory primary. Kilowatts are the universal SI-canonical primary power unit for EU regulatory-and-engineering documentation globally. Stay in horsepower when the destination is a US-customary automotive engine spec, US-import consumer-automotive marketing, US-customary industrial-motor engineering documentation, US-customary EV marketing, US-import marine-engine marketing, or any US-trained engineering or marketing context where mechanical horsepower is the consumer-recognition unit. The conversion is at the US-customary-hp source to metric-kW destination boundary, with the hp-figure on the US-customary side and the kW-figure on the EU-receiving-market regulatory documentation.
Common mistakes converting hp to kW
- Multiplying hp by 0.75 instead of 0.7457 for engineering-precision work. The 0.6% rounding is acceptable for casual conversion but fails type-approval-precision specifications. The full 0.7457 multiplier is required for EU type-approval submissions and EN 60034 industrial-motor regulatory documentation.
- Confusing US-customary mechanical hp (0.7457 kW per hp) with continental European metric PS (0.7355 kW per PS). The two units differ by 1.4%, and substituting one for the other in cross-jurisdictional automotive-engineering specs produces measurable error.
Frequently asked questions
How many kW in 1 hp?
One mechanical horsepower (US-customary) equals exactly 0.7457 kW (specifically 745.69987 W) at the precise SI-derived definition. One metric horsepower (PS, continental European) equals 0.7355 kW (735.49875 W). The two definitions differ by 1.4%.
How many kW in 200 hp (a typical US light truck)?
Two hundred mechanical horsepower equals 200 × 0.7457 = 149.1 kW, typically rounded to 149 kW on EU-export marketing materials. That is a typical US-light-truck engine rating translated for EU regulatory-primary documentation.
How many kW in 1020 hp (Tesla Model S Plaid)?
One thousand and twenty mechanical horsepower equals 1020 × 0.7457 = 760.6 kW, typically rounded to 760 kW on EU-marketing materials. That is the Tesla Model S Plaid peak motor power across three motors, with the hp-figure on the US-customary marketing and the kW-figure on the EU-marketing.
Quick way to convert hp to kW in my head?
Multiply the hp figure by 0.75 — essentially identical precision to the precise 0.7457 factor. For 200 hp the shortcut gives 150 kW versus the precise 149 kW. The cruder "× 0.7" shortcut understates by 6% and is fine for very rough approximation only.
Why are mph and PS different sizes?
Mechanical horsepower (US-customary) was defined by James Watt around 1782 as 33,000 foot-pounds per minute = 745.7 W. Metric horsepower (PS, continental European) was defined as the metric-equivalent of the imperial figure rounded to convenient metric values, giving 735.5 W. The 1.4% difference reflects the different rounding conventions in the two systems.
When does hp-to-kW appear in real work?
Hp-to-kW appears in US-customary hp automotive engine ratings translated to EU-export kW regulatory primary, US-customary hp industrial-motor ratings translated to EN 60034 EU-export kW, US-customary hp marine-engine ratings translated to kW EU-export documentation, and US-customary hp generator-set ratings translated to kW EU-receiving-market documentation. The conversion runs at every US-customary-hp source to metric-kW destination boundary in cross-Atlantic engineering and export-marketing work. Each case translates US-customary mechanical-hp into SI-canonical kW EU regulatory primary.
How precise should hp-to-kW be for type-approval work?
For EU-jurisdiction vehicle type-approval submissions the precise 0.7457 multiplier is required because EU type-approval documentation has tight tolerance bands on engine-power specification accuracy. The "× 0.75" shortcut is essentially identical precision; the "× 0.7" shortcut introduces 6% error large enough to fail type-approval-precision specifications.