Energy & Power Converters
4 tools in this collection — free, instant, and private in your browser.
Energy and power are related but distinct concepts that are frequently confused. Power is the rate at which energy is produced or consumed — it describes how fast work is done. Energy is the total amount of work done over time. Understanding this difference is important when comparing engines, evaluating electricity bills, or specifying industrial equipment.
In automotive and mechanical contexts, engine output is most often given in horsepower (hp) in the United States and kilowatts (kW) in metric countries. One mechanical horsepower equals approximately 0.7457 kilowatts, so a 200 hp engine produces about 149 kW. Electric vehicles have made this conversion particularly relevant as manufacturers increasingly list motor output in kilowatts while buyers accustomed to combustion engines think in horsepower.
Energy itself is measured in joules (the SI unit), kilowatt-hours (kWh, used for electricity billing), BTUs (British Thermal Units, used in heating and cooling), and calories (used in chemistry and nutrition). A kilowatt-hour equals 3,600,000 joules or approximately 3,412 BTUs, numbers that matter when comparing heating systems or sizing solar panel installations.
- Use Horsepower to Kilowatts or Kilowatts to Horsepower when comparing vehicle specifications across markets.
- Use the Power Converter when working with less common units like metric horsepower, foot-pounds per second, or watts in industrial contexts.
- Use the Energy Converter when switching between joules, BTUs, calories, and kilowatt-hours for heating, electrical, or scientific applications.
Accurate energy and power conversion is essential in engineering, purchasing decisions, and environmental calculations where small errors can translate into significant cost differences or equipment mismatches.
All energy & power converters
All converter tools →Compare these tools
| Tool | What it does |
|---|---|
| Energy Converter | Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, and electron volts. |
| Horsepower to Kilowatts | Convert horsepower to kilowatts instantly. Free, fast, no signup. |
| Kilowatts to Horsepower | Convert kilowatts to horsepower instantly. Free, fast, no signup. |
| Power Converter | Convert power between watts, kilowatts, megawatts, horsepower, BTU per hour, and calories per second. |
Frequently asked questions
- How do I convert horsepower to kilowatts?
- Multiply horsepower by 0.7457 to get kilowatts. A 300 hp engine produces approximately 224 kW. Note that metric horsepower (PS or CV), common in European car specs, is slightly different: 1 PS equals 0.7355 kW.
- What is the difference between energy and power?
- Power is the rate of energy use or production, measured in watts or horsepower. Energy is power multiplied by time, measured in kilowatt-hours or joules. A 1,000-watt (1 kW) appliance running for one hour consumes 1 kilowatt-hour of energy.
- How many BTUs are in a kilowatt-hour?
- One kilowatt-hour equals approximately 3,412 BTUs. This conversion is useful when comparing electric heating to gas or oil heating systems, which are often rated in BTUs per hour.