Mechanical horsepower.
Horsepowers to Kilowatts Converter — hp to kW
Convert Horsepower (hp) to Kilowatt (kW) using the exact conversion factor (1 horsepower = 0.7456998716 kilowatt). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Horsepowers to Kilowatts converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Kilowatt is 1000 watt units.
Result = input x 745.6998716 / 1000.
Power units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Horsepowers to Kilowatts
Horsepower and Kilowatt both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Horsepower is typically associated with united States and United Kingdom (vehicle and engine specifications), while Kilowatt is typically associated with standard power unit worldwide for larger appliances, vehicles, and electrical systems.
Formula
kilowatts = horsepowers × 0.745699871582
This factor comes from each unit's defined relationship to the category's base unit: 1 horsepower equals 745.699871582 base units, and 1 kilowatt equals 1000 base units, so dividing one by the other gives the direct horsepower-to-kilowatt factor of 0.745699871582.
Simple example
1 hp × 0.7456998716 = 0.7456998716 kW
1 horsepower = 0.7456998716 kilowatts.
Real-world example
100 hp × 0.7456998716 = 74.56998716 kW
100 horsepowers = 74.56998716 kilowatts.
Conversion table
| Horsepower (hp) | Kilowatt (kW) |
|---|---|
| 1 hp | 0.7456998716 kW |
| 10 hp | 7.456998716 kW |
| 50 hp | 37.28499358 kW |
| 100 hp | 74.56998716 kW |
| 500 hp | 372.8499358 kW |
| 1,000 hp | 745.6998716 kW |
Reverse conversion: Kilowatt to Horsepower
0.7456998716 kW × 1.34102209 = 1 hp
0.7456998716 kilowatts = 1 horsepowers.
horsepowers = kilowatts × 1.3410220896
For a page dedicated to this direction, see Kilowatt to Horsepower.
Horsepower vs. Kilowatt
| Aspect | Horsepower | Kilowatt |
|---|---|---|
| Family | US/imperial customary unit | SI derived (metric prefix) unit |
| Typical use | US and UK vehicle engine power ratings | Electric vehicle motor power ratings (alongside horsepower) |
| Where it's used | United States and United Kingdom (vehicle and engine specifications) | Standard power unit worldwide for larger appliances, vehicles, and electrical systems |
Understanding the Horsepower
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
Where it's used: United States and United Kingdom (vehicle and engine specifications)
Mechanical horsepower vs. metric horsepower. Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Uses of the Horsepower today
- US and UK vehicle engine power ratings
- Motor and engine specifications in English-speaking markets
History of the Horsepower
James Watt popularized horsepower in the 1780s as a marketing figure, comparing his steam engines' output to the working capacity of a horse (based on his estimate of a horse turning a mill), so buyers could grasp engine capability in familiar terms. The unit stuck long after its origin as a sales tool, eventually being formally defined at exactly 550 foot-pounds per second.
Historical origin. Horsepower was not the invention of a single named person; it developed through the process described above.
Understanding the Kilowatt
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard power unit worldwide for larger appliances, vehicles, and electrical systems
Uses of the Kilowatt today
- Electric vehicle motor power ratings (alongside horsepower)
- Household electrical system and generator capacity
- Industrial motor and equipment power ratings
History of the Kilowatt
The kilowatt follows directly from the watt via the standard SI 'kilo-' prefix, becoming especially prominent with the growth of electrical power generation and distribution in the late 19th and 20th centuries.
Historical origin. Kilowatt was not the invention of a single named person; it developed through the process described above.
Horsepower — sources
- NIST Special Publication 811 — Documents the exact watt-equivalence of mechanical horsepower.
Kilowatt — sources
- BIPM SI Brochure — SI prefixes — Defines 'kilo-' as the prefix for 10³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilowatts are in 1 horsepower?
1 horsepower equals 0.7456998716 kilowatts, using the exact defined conversion factor rather than an estimate.
How do I convert horsepower to kilowatt?
Multiply the horsepower value by 0.7456998716. The converter above does this instantly to whatever precision you set.
How do I convert kilowatt back to horsepower?
Use the reverse factor: 1 kilowatt equals 1.34102209 horsepowers. You can also use the swap control in the converter above to flip the direction instantly.
What is a horsepower?
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
What is a kilowatt?
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Is the horsepower to kilowatt conversion exact?
Yes. Mechanical horsepower is defined as exactly 745.6998715822702 watts. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between mechanical horsepower vs. metric horsepower?
Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Where is the horsepower still used today?
United States and United Kingdom (vehicle and engine specifications)