AJ Designer

Power Unit Converter

Result equals value times the ratio of conversion factors

Power Conversion =

1 Watt (W) = 0.0013410221 Horsepower (hp); 0.001 Kilowatt (kW)

Solution in Other Units

UnitValue
Watt (W)1
Kilowatt (kW)0.001
Megawatt (MW)1e-6
Horsepower (hp)0.0013410221
Foot-Pound / Second (ft·lbf/s)0.73756215

Show Your Work

Result = Value × (Source factor ÷ Target factor)
Base unit for this power family is Watt (W).
1 Watt (W) = 1 Watt (W)
1 Watt (W) = 0.0013410221 Horsepower (hp)
1 Watt (W) = 0.001 Kilowatt (kW)
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How It Works

This converter uses the watt (W) as its base unit, which is one joule of energy transferred per second. Each supported power unit has a known factor relative to the watt, so the calculator converts your input into watts first and then divides by each target-unit factor to populate the full power table.

Example Problem

Convert 7.5 horsepower to watts and kilowatts for an equipment comparison.

  1. Start with the source value: 7.5 hp.
  2. Use the common factor 1 hp ≈ 745.7 W.
  3. Convert to the base unit: 7.5 × 745.7 = 5,592.75 W.
  4. Convert watts to kilowatts: 5,592.75 ÷ 1,000 = 5.59275 kW.
  5. So the same output is 5,592.75 W.
  6. That is also about 5.593 kW.

Key Concepts

Power is the rate at which energy is transferred or work is done. The SI base unit is the watt, but many industries also use kilowatts, horsepower, megawatts, and foot-pounds per second. Because power units all describe the same underlying dimension, conversion is a direct factor-based process through the watt.

Applications

  • Electrical engineering: comparing device ratings in watts, kilowatts, and megawatts
  • Motors and engines: translating horsepower to watts or kilowatts for specification sheets
  • HVAC design: comparing blower, compressor, and fan power across different rating systems
  • Mechanical analysis: converting foot-pound-per-second values into standard electrical power units

Common Mistakes

  • Confusing power and energy, such as treating kilowatts and kilowatt-hours as if they were interchangeable
  • Mixing different horsepower definitions without checking which one a vendor or textbook uses
  • Rounding the horsepower-to-watt factor too early when later efficiency or load calculations depend on it

Frequently Asked Questions

How do you convert power units?

Convert the source value to watts first, then divide by the target-unit factor. That is the base-unit method this calculator uses.

What is the formula for converting watts, kilowatts, and horsepower?

Use Result = Value × (source factor ÷ target factor), where each factor is defined relative to the watt.

How many watts are in 1 horsepower?

One mechanical horsepower is about 745.7 watts.

What is the difference between watts and kilowatts?

A kilowatt is 1,000 watts, so larger equipment is often easier to express in kW.

Is foot-pound per second a power unit?

Yes. It measures work per unit time and can be converted directly to watts or horsepower.

Why do engines often use horsepower?

Horsepower remains a familiar and practical rating unit in automotive, industrial, and legacy mechanical applications.

Can I use this converter for motors, engines, and electrical loads?

Yes. As long as the quantity is power, the calculator can translate it across the supported units.

Power Conversion Formula

Power conversions use the watt as the common base unit. The calculator converts the source rate of energy transfer into watts first, then expresses that same power in every other supported unit below.

Result = Value × (Source factor ÷ Target factor)
  • Result — the converted measurement in the target power unit
  • Value — the original measurement you enter
  • Source factor — the factor that maps the source unit to the common base unit
  • Target factor — the factor used to express the same base-unit value in the target unit

Worked Examples

Motor Sizing

How do you convert 5 horsepower to kilowatts?

A motor nameplate uses horsepower, but an electrical spec sheet uses kilowatts.

  • Start with the source value: 5 hp.
  • Use the conversion 1 horsepower ≈ 745.7 W.
  • Multiply: 5 × 745.7 = 3,728.5 W.
  • Convert watts to kilowatts: 3,728.5 ÷ 1,000 = 3.7285 kW.
  • The same power is also 3.7285 kW.
  • So 5 horsepower is about 3.73 kilowatts.

A power rating of 5 hp is about 3.73 kW.

This is a common motor and compressor sizing conversion.

Electrical Load

What is 1,500 watts in horsepower?

An appliance or machine load is listed in watts, but you want an intuitive horsepower comparison.

  • Start with the source value: 1,500 W.
  • Use the horsepower factor 1 hp ≈ 745.7 W.
  • Divide: 1,500 ÷ 745.7 ≈ 2.0115 hp.
  • That is also 1.5 kW.
  • So the load is just over 2 horsepower.
  • The same power is about 2.01 hp.

A load of 1,500 W is about 2.01 hp.

This helps when comparing electric motors with legacy mechanical equipment ratings.

Mechanical Work Rate

How do you convert 10,000 foot-pounds per second to horsepower?

A rotating system calculation produces ft·lbf/s and needs to be compared with horsepower ratings.

  • Start with the source value: 10,000 ft·lbf/s.
  • One horsepower equals 550 ft·lbf/s.
  • Divide by 550: 10,000 ÷ 550 = 18.1818 hp.
  • You can also convert directly to watts.
  • 10,000 ft·lbf/s ≈ 13,558.18 W.
  • The same power is about 18.18 hp.

A mechanical power rate of 10,000 ft·lbf/s is about 18.18 hp.

This is useful in legacy mechanical design references and older machinery documentation.

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