Power Converter

Power is one of the most important quantities in a unit converter because people deal with it every day. Every time you see a charger rated 20 W, a fan rated 75 W, a motor rated 2 hp, a solar system rated 5 kW, or an electricity plant rated 800 MW, you are looking at power. Power tells you how fast energy is being used, produced, or transferred.

An advanced power unit converter with 76 units covers everything from tiny electronic signals measured in microwatts, all the way up to giant grid outputs measured in gigawatts, plus engine units like horsepower and thermal units like BTU per hour.

What Power Means

Power is the rate of doing work or transferring energy.

Power equals energy divided by time

That means power always describes “how much per second” or “how much per hour” depending on the unit.

The SI unit of power is the watt.

1 watt equals 1 joule per second

So if a device uses 300 joules in one second, it is using 300 watts of power.

Power Versus Energy

Many users confuse power with energy, so a good converter page explains this clearly.

Power is the rate at which energy is used or produced. It is measured in watts, kilowatts, horsepower, BTU per hour, and so on.

Energy is the total amount used or produced over time. It is measured in joules, kilowatt hours, calories, BTU, and so on.

A simple example

A 1000 watt heater running for 2 hours uses energy equal to 1000 watts times 2 hours, which equals 2000 watt hours, or 2 kilowatt hours.

So the heater rating is power, but your electricity bill measures energy.

Why There Are So Many Power Units

Different industries developed their own power units for practical reasons.

Electrical and electronics industries use watts because it connects directly to voltage and current.

Vehicles and engines use horsepower because it became a practical way to describe engine strength.

Heating and cooling use BTU per hour and tons of refrigeration because those match heat transfer needs.

Large scale energy production uses megawatts and gigawatts because watts are too small for power plants.

AC electrical systems use VA and var because real power is not the same as apparent power when the power factor is not 1.

That is why a full converter needs many units to support all real world use cases.

How a Power Unit Converter Works

Most power converters choose watts as the internal base unit.

The converter stores a conversion factor for each unit.

Step one it converts the input value into watts

Step two it converts watts into the selected output unit

This approach lets you convert any unit into any other unit, even if they come from different systems like SI, imperial, mechanical, or thermal.

The 76 Power Units in a Converter

Below is a complete list of 76 power units commonly included in a full featured unit converter. They are grouped for clarity.

SI Metric Watt Units and Prefix Units

• Attowatt aW
• Femtowatt fW
• Picowatt pW
• Nanowatt nW
• Microwatt µW
• Milliwatt mW
• Centiwatt cW
• Deciwatt dW
• Watt W
• Decawatt daW
• Hectowatt hW
• Kilowatt kW
• Megawatt MW
• Gigawatt GW
• Terawatt TW
• Petawatt PW
• Exawatt EW

These cover almost all electrical and modern power usage. Small units are used in electronics and sensors. Larger units are used in industry, solar systems, wind turbines, and power plants.

Joule per Time Units

• Joule per second J per s
• Kilojoule per second
• Megajoule per second
• Gigajoule per second
• Terajoule per second

These are scientific forms of expressing power. Joule per second is exactly the same as watt, but the wording is used in physics and engineering to emphasize energy transfer per time.

Horsepower and Engine Related Units

• Horsepower mechanical hp
• Horsepower metric PS
• Horsepower electric
• Horsepower boiler
• Horsepower water
• Horsepower shaft
• Horsepower hydraulic
• Millihorsepower

Horsepower is used for engines, motors, pumps, and vehicle performance. Multiple horsepower types exist because different industries defined horsepower slightly differently, so converters separate them for accuracy.

Thermal and HVAC Power Units

• BTU per second
• BTU per minute
• BTU per hour
• BTU IT per hour
• BTU thermochemical per hour
• Ton of refrigeration
• Kiloton of refrigeration

These are used in heating and cooling systems. Air conditioners are commonly rated in BTU per hour or tons of refrigeration.

Important note

BTU is energy, but BTU per hour is power.

Electrical Engineering Apparent and Reactive Power Units

• Volt ampere VA
• Kilovolt ampere kVA
• Megavolt ampere MVA
• Gigavolt ampere GVA
• Volt ampere reactive var
• Kilovar kvar
• Megavar Mvar
• Gigavar Gvar

These appear in AC electrical systems.

Real power measured in W or kW is the useful power that performs work like turning motors or heating.

Apparent power measured in VA or kVA is what the electrical system must supply based on voltage and current.

Reactive power measured in var or kvar is associated with magnetic and electric fields in inductors and capacitors. It does not directly produce useful work but affects system loading.

This is why generators and transformers are often rated in kVA instead of kW.

Metric Force Based Mechanical Power Units

• Newton meter per second
• Kilonewton meter per second
• Newton per second
• Kilonewton per second
• Meter kilogram force per second
• Meter kilogram force per minute
• Kilogram force meter per second
• Kilogram force meter per minute

These appear in mechanical engineering, torque power calculations, and legacy metric force systems.

Imperial Force Based Mechanical Power Units

• Foot pound force per second
• Foot pound force per minute
• Foot pound force per hour
• Inch pound force per second
• Inch pound force per minute
• Pound force foot per second
• Pound force foot per minute
• Pound force inch per second
• Pound force inch per minute
• Ton force foot per second

These appear in older engineering documents, mechanical references, and some industrial calculation sets.

CGS System Units

• Erg per second
• Kilerg per second
• Megerg per second
• Gigerg per second

These are commonly seen in older scientific literature and some astronomy texts.

Calorie Based Power Units

• Calorie per second
• Calorie per minute
• Calorie per hour
• Kilocalorie per second
• Kilocalorie per minute
• Kilocalorie per hour

These appear in fitness, nutrition, and metabolism discussions, because burning calories per time is a form of power.

Extra Specialized and Reference Units

• Pferdestarke per second reference
• Ton force foot per second alternative reference
• Micropower reference unit
• Some converter catalogs include these extra labels for completeness.

Key Ideas That Make Power Conversion Easier

Watts are the foundation. Many units can be understood by converting to watts first.

If you are converting between motor ratings, horsepower and kilowatts are the most common pair.

If you are converting between heating and electrical power, watts and BTU per hour are the most common pair.

If you are converting generator ratings, kVA and kW require power factor knowledge.

Practical Examples With Full Working

Example 1 Convert 2 kilowatts to mechanical horsepower

A commonly used relationship is that 1 mechanical horsepower is about 745.7 watts.

Step one convert kilowatts to watts

2 kilowatts equals 2000 watts

Step two convert watts to horsepower

Horsepower equals 2000 divided by 745.7

2000 divided by 745.7 equals 2.681

Result

2 kW is approximately 2.68 hp

Example 2 Convert 1500 watts to kilowatts

1 kilowatt equals 1000 watts.

1500 watts divided by 1000 equals 1.5

Result

1500 W equals 1.5 kW

This is a common conversion when reading appliance labels.

Example 3 Convert 3 kW to BTU per hour

A commonly used relationship is that 1 watt equals about 3.412142 BTU per hour.

First convert 3 kW to watts

3 kW equals 3000 W

Now convert to BTU per hour

3000 times 3.412142 equals 10236.426

Result

3 kW is approximately 10,236.43 BTU per hour

This is useful when comparing electric heaters to heating system ratings.

Example 4 Convert kVA to kW using power factor

This is a real world electrical engineering concept.

Real power kW equals apparent power kVA times power factor

If you have a generator rated 10 kVA and the power factor is 0.8

kW equals 10 times 0.8

kW equals 8

So 10 kVA at power factor 0.8 provides 8 kW of real usable power.

This explains why two generators with the same kVA rating may deliver different kW depending on load conditions.

Common Mistakes People Make With Power Units

One mistake is mixing kW and kWh. kW is power, kWh is energy.

Another mistake is mixing BTU and BTU per hour. BTU is energy, BTU per hour is power.

Another mistake is assuming kVA equals kW. It is only equal when power factor is 1.

Another mistake is assuming horsepower is always identical. Different horsepower definitions exist, so users should pick the correct horsepower type.

Power is the rate of energy transfer and is used in electrical devices, engines, heating systems, and grid scale energy production. A complete converter with 76 power units supports SI watt units, multiple horsepower types, HVAC units like BTU per hour and tons of refrigeration, AC electrical units like VA and var, and legacy mechanical units. Try the calculator above to see your results.