KWh to Watt Calculator
Calculate power from energy and time, or convert between energy and power units
Table of Contents
How to Use
- Select calculation mode: Power calculation or Unit conversion
- For power calculation: Enter energy value, energy unit, time value, and time unit
- For unit conversion: Enter value, select from/to units, and calculate
- View results with conversion formulas and all unit equivalents
- Use the recalculate button to perform new calculations
Power and Energy Relationship
Power is the rate at which energy is transferred or consumed. The relationship between power, energy, and time is fundamental in physics and engineering: Power = Energy ÷ Time.
Understanding this relationship is essential for electrical calculations, energy efficiency analysis, and power system design.
Energy Units
| Unit | Symbol | Joules Equivalent | Common Use |
|---|---|---|---|
| Kilowatt-hour | kWh | 3,600,000 J | Electricity bills, large energy consumption |
| Watt-hour | Wh | 3,600 J | Batteries, small devices |
| Joule | J | 1 J | SI base unit, physics |
| British Thermal Unit | BTU | 1,055.06 J | Heating/cooling systems |
| Calorie | cal | 4.184 J | Food energy, chemistry |
Power Units
| Unit | Symbol | Watts Equivalent | Common Use |
|---|---|---|---|
| Watt | W | 1 W | SI base unit, small devices |
| Kilowatt | kW | 1,000 W | Household appliances, motors |
| Horsepower | hp | 745.7 W | Engines, motors (US) |
Frequently Asked Questions
- How do I calculate power from energy and time?
- Use the formula: Power = Energy ÷ Time. For example, if you consume 2 kWh of energy in 4 hours, the power is 2 kWh ÷ 4 h = 0.5 kW = 500 W.
- What's the difference between energy and power?
- Energy is the total amount of work done or heat transferred, measured in units like kWh or joules. Power is the rate at which energy is used or transferred, measured in units like watts or kilowatts. Power = Energy ÷ Time.
- How do I convert kWh to watts?
- To convert kWh to watts, you need to know the time period. For example, 1 kWh used over 1 hour = 1 kW = 1,000 W. If 1 kWh is used over 2 hours, the power is 0.5 kW = 500 W.
- What is horsepower and how does it relate to watts?
- Horsepower is a unit of power commonly used for engines and motors. 1 horsepower = 745.7 watts. It's primarily used in the US for automotive and industrial applications.