Power Conversion Calculator

Power Conversion

Power Value

From Unit Watts (W) Kilowatts (kW) Megawatts (MW) Gigawatts (GW) Horsepower (hp) BTU per hour (BTU/h) Kilocalories per hour (kcal/h) Foot-pounds per second (ft-lb/s)

To Unit Watts (W) Kilowatts (kW) Megawatts (MW) Gigawatts (GW) Horsepower (hp) BTU per hour (BTU/h) Kilocalories per hour (kcal/h) Foot-pounds per second (ft-lb/s)

Decimal Precision 2 decimals 4 decimals 6 decimals 8 decimals

Scientific Notation Auto Always Never

Power Unit Information:

1 Watt = 1 Joule/second | 1 kW = 1000 Watts | 1 hp = 745.7 Watts

Learn more about power units

Conversion Results

100 W = 0.1 kW

Unit	Value	Equivalent To
Watts (W)	100.0000	1.0000 W
Kilowatts (kW)	0.1000	1000.0000 W
Horsepower (hp)	0.1341	745.7000 W

Base Unit

Watts (W)

Conversion Factor

0.0010

Precision

4 decimals

Scientific Notation

Disabled

Common Power Conversions:

1 kW = 1.341 hp | 1 hp = 0.7457 kW | 1 BTU/h = 0.2931 W

View all conversion factors

Calculation History

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© 2023 Power Conversion Calculator | All calculations are for reference only

Master Power Conversion

Your Complete Guide to Understanding and Converting Between Power Units

Have you ever wondered how many light bulbs a car engine could power? Or how to compare your home's electricity usage to a wind turbine's output? Understanding power conversion is like having a universal translator for energy - it helps you make sense of everything from household appliances to industrial machinery.

In this comprehensive guide, we'll break down power conversion into simple, easy-to-understand concepts with real-world examples and our interactive calculator that does all the math for you.

What Is Power Anyway?

Power is the rate at which energy is used, transferred, or converted. Think of it as how fast energy is "spent." If energy is like money in your bank account, power is how fast you're spending it.

Simple Example:

A 60-watt light bulb uses 60 joules of energy every second. That means:

• Power = 60 watts
• This is the "speed" at which it uses electricity
• Leave it on for 10 hours, and you've used 600 watt-hours of energy

The Main Power Units Explained

Different situations use different power units. Here are the most common ones:

Unit	Symbol	What It Means	Common Uses
Watt	W	1 joule per second	Light bulbs, electronics, small appliances
Kilowatt	kW	1,000 watts	Household electricity, larger appliances
Horsepower	hp	About 746 watts	Cars, engines, motors
BTU/hour	BTU/h	British Thermal Unit per hour	Heating and cooling systems
Megawatt	MW	1,000,000 watts	Power plants, large industrial equipment

The Simple Conversion Formula

The Basic Conversion Rule:

Target Value = (Original Value × Original Factor) ÷ Target Factor

Where each unit has a specific "conversion factor" to watts

Example: Converting 100 Watts to Horsepower

We know:

• 1 horsepower = 745.7 watts
• So: horsepower = watts ÷ 745.7
• 100 watts ÷ 745.7 = 0.134 horsepower

A 100-watt device produces about 0.134 horsepower - that's like a very small electric motor!

Real-World Power Comparisons

Around Your Home

• LED Light Bulb: 10 watts
• Laptop Computer: 50 watts
• Microwave Oven: 1,200 watts (1.2 kW)
• Air Conditioner: 1,500-5,000 watts (1.5-5 kW)
• Electric Water Heater: 4,500 watts (4.5 kW)

Transportation

• Electric Bicycle: 250-750 watts
• Compact Car Engine: 100-150 horsepower (75-112 kW)
• Family SUV Engine: 200-300 horsepower (150-224 kW)
• Electric Car Motor: 200-500 horsepower (150-373 kW)

Fun Fact: Your Car vs Your House

A typical family car (150 hp) produces about 112,000 watts. That's enough to power:

• 11,200 LED light bulbs (10W each)
• 93 microwaves (1,200W each)
• About 10 average homes (using 1,100W average)

How to Use the Power Conversion Calculator

Step 1: Enter Your Power Value

Type in the number you want to convert. This could be:

• The wattage of an appliance (like "100" for a 100W bulb)
• The horsepower of a motor (like "2.5" for a small engine)
• The kilowatt rating of a device (like "1.5" for a heater)

Step 2: Select "From" and "To" Units

Choose what unit you're starting with and what unit you want to convert to:

• From: The unit of your original number
• To: The unit you want to convert to

Pro Tip: Common Conversions

Some conversions you'll use often:

• Watts to Horsepower: Divide by 745.7
• Horsepower to Kilowatts: Multiply by 0.7457
• BTU/h to Watts: Multiply by 0.2931
• Kilowatts to Watts: Multiply by 1,000

Step 3: Use Advanced Options (Optional)

Click "Advanced Options" to control:

• Decimal Precision: How many decimal places to show
• Scientific Notation: For very large or very small numbers

Key Features of Our Calculator

Calculation History

Automatically saves your calculations so you can review or reuse them later.

Visual Charts

See your conversion results in easy-to-understand bar charts.

Export Options

Save results as PDF, HTML, or text files for reports or sharing.

Copy Results

One-click copying of conversion results to your clipboard.

Practical Applications

For Homeowners

• Appliance Comparison: Compare energy usage of different devices
• Solar Planning: Convert solar panel outputs to household usage
• Energy Bills: Understand your electricity usage in different units

For Engineers and Technicians

• Motor Selection: Convert between horsepower and kilowatts
• HVAC Design: Convert between BTU/h and watts for heating systems
• International Projects: Convert between metric and imperial units

For Students and Teachers

• Physics Problems: Quickly check unit conversions
• Science Projects: Compare energy outputs in different units
• Lab Work: Convert experimental results to standard units

Frequently Asked Questions (15 Common Questions)

1. What's the difference between power and energy?

Power is the rate of energy use (like speed), while energy is the total amount used (like distance traveled). Power is measured in watts; energy is measured in watt-hours or joules.

2. Why is horsepower still used if we have watts?

Horsepower is traditional and familiar, especially for engines and motors. It dates back to James Watt comparing steam engines to horses. Many industries and consumers still think in horsepower terms.

3. How many watts are in one horsepower exactly?

Exactly 745.699872 watts. Most calculations use 745.7 or 746 watts for simplicity. Our calculator uses 745.7 for precise conversions.

4. What's a kilowatt-hour (kWh)?

A kilowatt-hour is a unit of energy (not power). It's the energy used by a 1,000-watt device running for 1 hour. Your electricity bill is in kWh, which measures total energy used.

5. Can I convert power units to energy units?

No, they're different types of measurements. Power units (watts, hp) measure rate. Energy units (joules, kWh) measure total amount. But you can calculate energy from power if you know time: Energy = Power × Time.

6. What's a megawatt and when is it used?

A megawatt (MW) is 1 million watts. Used for large-scale power: power plants (500+ MW), wind turbines (2-8 MW each), large factories. Your home might use 1-2 kW; a city needs MW.

7. How accurate are the conversion factors?

Our calculator uses industry-standard conversion factors accurate to 6+ decimal places. For most practical purposes, 2-4 decimal places is sufficient.

8. What's the relationship between BTU/h and tons of cooling?

In air conditioning, 1 ton of cooling = 12,000 BTU/h. So a 3-ton AC unit = 36,000 BTU/h = about 10.55 kW. This dates back to melting 1 ton of ice in 24 hours.

9. Can I use this calculator for mechanical vs electrical power?

Yes! The calculator converts between units regardless of the power type. But remember: mechanical horsepower (hp) and electrical horsepower are slightly different (746W vs 746W exactly). We use the standard 745.7W.

10. What's a gigawatt and is it realistic?

A gigawatt (GW) is 1 billion watts. Large nuclear power plants produce about 1 GW. The famous "1.21 gigawatts" from Back to the Future would power about 750,000 homes!

11. How do I convert watts to amps?

Watts to amps requires knowing voltage: Amps = Watts ÷ Volts. For example, a 1,200W device at 120V uses 10 amps. Our calculator doesn't do this directly, but you can calculate it separately.

12. What's foot-pound per second (ft-lb/s)?

A mechanical power unit: 1 ft-lb/s = 1.3558 watts. It's the power needed to lift 1 pound 1 foot in 1 second. Rarely used today but still in some engineering fields.

13. Can I save my calculations for later?

Yes! Our calculator automatically saves to your browser's history. You can also export results as files (PDF, HTML, TXT) to keep permanent records.

14. What's the most common conversion people need?

Watts to horsepower (for understanding car/motor power) and kW to BTU/h (for heating/cooling systems) are the most common conversions we see.

15. Is there a mobile app version?

Our calculator works perfectly on mobile browsers! Save it to your home screen for app-like access. It's fully responsive and works offline for basic calculations.

Final Tips for Power Conversion Success

Quick Reference Guide

• Remember: 1 kW = 1,000 W = 1.341 hp
• For cars: Multiply hp by 0.7457 to get kW
• For AC units: Divide BTU/h by 3,412 to get kW
• For appliances: Check labels for wattage ratings

Understanding power conversion opens up a whole new world of energy literacy. Whether you're comparing electric cars, planning a solar installation, or just curious about how much power your gadgets use, this knowledge puts you in control.

Our calculator takes the complexity out of conversions, letting you focus on what matters: making informed decisions about energy use.