HP to KW Converter

Relationship Between Horsepower and Kilowatt

The conversion between horsepower (hp) and kilowatt (kW) is a fundamental power unit conversion between imperial and metric systems.

1 hp = 745.699872 W

Since 1 kW = 1,000 W,

1 hp = 0.7457 kW

Therefore,

1 kW = 1.34102 hp

To convert horsepower to kilowatts, we multiply the value in horsepower by 0.7457 (or divide by 1.34102).

For example, 1 hp equals approximately 0.7457 kW, and 100 hp equals approximately 74.57 kW. A typical car engine producing 150 hp is equivalent to approximately 112 kW.

Quick Reference:
Horsepower is commonly used in the automotive, marine, and industrial sectors, especially in the United States. The kilowatt is the standard metric unit used worldwide for larger power measurements. Understanding horsepower to kilowatt conversion is essential for comparing engine and motor ratings across different measurement standards.

Horsepower (hp)

What is Horsepower?

Horsepower (symbol: hp) is a unit of power in the imperial and US customary systems. It was originally defined by James Watt to compare the output of steam engines with the power of draft horses. Today, mechanical horsepower is defined as exactly 745.699872 watts, making it a convenient unit for measuring engine and motor power.

Historical Background

Horsepower was developed by James Watt in the late 18th century to market his steam engines. He calculated that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute), and the wheel was 12 feet in radius. This led to the definition of 1 horsepower as the ability to lift 550 pounds by 1 foot in 1 second, which equals 33,000 foot-pounds per minute or approximately 745.7 watts.

Types of Horsepower

• Mechanical horsepower (hp): The standard definition, equal to 745.699872 W, commonly used in the United States and United Kingdom
• Metric horsepower (PS): Used in Europe, equal to 735.49875 W (slightly different from mechanical hp)
• Electric horsepower: Equal to 746 W, used for electric motors
• Boiler horsepower: Used for steam boilers, equal to 33,475 BTU/h or approximately 9,809.5 W
• Hydraulic horsepower: Used in hydraulic systems, calculated based on pressure and flow rate

Common Applications

• Automotive: Car engines (100-700 hp typical), trucks (200-600 hp), motorcycles (50-200 hp)
• Marine: Boat engines (50-5000 hp), outboard motors (5-450 hp)
• Industrial: Manufacturing equipment, pumps, compressors (1-1000 hp)
• Agricultural: Tractors (20-500 hp), combines, farm equipment
• Aircraft: Small aircraft engines (100-400 hp), large aircraft (thousands of hp)
• Construction: Heavy machinery, excavators, bulldozers (50-1000 hp)
• Power tools: Large industrial tools, generators
• Racing: High-performance vehicles (300-1500+ hp)
• Marine propulsion: Ship engines (hundreds to thousands of hp)
• Power generation: Backup generators, portable generators (1-500 hp)

Horsepower Standards

In the United States and United Kingdom, mechanical horsepower (hp) is the standard unit for engine and motor ratings. Understanding horsepower to kilowatt conversion is essential for comparing power ratings across different systems, especially when working with international standards or converting between metric and imperial units.

Kilowatt (kW)

What is a Kilowatt?

The kilowatt (symbol: kW) is a unit of power equal to 1,000 watts (1 kW = 1,000 W). It is commonly used to measure larger power values such as household appliances, electric motors, power generation, and energy consumption. The kilowatt provides convenient numerical values for power measurements that would be cumbersome to express in watts.

Power Measurement

As a metric unit, the kilowatt is part of the International System of Units (SI). 1 kW = 1,000 W = 1,000 J/s. The kilowatt is widely used in electrical engineering, energy management, and power generation because it provides manageable numbers for typical power values encountered in practice.

Common Applications

• Household power consumption: Average home uses 1-2 kW, peak usage 5-10 kW
• Electric appliances: Electric water heaters (3-5 kW), air conditioners (2-5 kW), electric stoves (2-4 kW)
• Electric motors: Industrial motors (1-100 kW), vehicle motors (50-300 kW)
• Power generation: Solar panel systems (1-10 kW residential, 100 kW-1 MW commercial)
• Wind power: Small turbines (1-10 kW), large turbines (1-5 MW)
• Energy storage: Home battery systems (5-20 kW), grid-scale storage (MW to GW)
• Electric vehicles: Charging stations (7-50 kW standard, 150-350 kW fast charging)
• Industrial equipment: Manufacturing machinery (10-500 kW), pumps and compressors (5-100 kW)
• Commercial buildings: Office buildings (50-500 kW), shopping centers (500 kW-5 MW)
• Power distribution: Residential service (10-50 kW), commercial service (100 kW-1 MW)

Kilowatt-Hour (kWh)

The kilowatt-hour (kWh) is a unit of energy commonly used for electricity billing. It represents the amount of energy consumed when a power of 1 kilowatt is used for 1 hour. For example, a 1 kW appliance running for 1 hour consumes 1 kWh of energy. Understanding the relationship between watts and kilowatts is essential for calculating energy consumption and electricity costs.

Conversion Benefits

Understanding kilowatt values helps in energy management, electrical system design, and power consumption analysis. The kilowatt provides convenient values for expressing power ratings of appliances, motors, and electrical systems, making it easier to understand and compare power requirements.

Horsepower to Kilowatt Conversion Table

Common horsepower to kilowatt conversions for reference: