Energy Converter Online
Free online energy converter. Convert between joules, calories, kilowatt-hours, BTU, electron volts, and more. Instant, precise results.
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Tip: Click any result row to instantly copy its value to clipboard
💡 Definition
Energy Converter
- Energy is the capacity to do work.
- The SI unit is the joule (J).
- Common alternatives include calories (nutrition), kilowatt-hours (electricity bills), and BTU (heating/cooling).
- This converter supports all major energy units.
📖 How to use
Step by Step
- Enter an energy value and choose your source unit from the Convert From dropdown
- All equivalent energy values appear instantly in the results grid
- The source unit row is highlighted in purple for clarity
- Click any result row to copy that value to your clipboard
🎯 Use cases
When to use
- Converting food calories to kilojoules
- Electricity usage and billing calculations
- HVAC and heating BTU calculations
- Physics and engineering energy analysis
Frequently Asked Questions
How many joules are in a calorie?▾
One thermochemical calorie equals 4.184 joules. One food Calorie (kcal) equals 4,184 joules or 4.184 kilojoules. Food labels use 'Calories' (uppercase) to mean kilocalories.
What is a kilowatt-hour?▾
A kilowatt-hour (kWh) is the energy consumed by a 1,000-watt appliance running for one hour. It equals 3,600,000 joules. It is the standard unit on electricity bills.
What is a BTU?▾
A British Thermal Unit (BTU) is the energy needed to raise the temperature of 1 pound of water by 1°F. One BTU equals approximately 1,055 joules. It is used in HVAC and heating systems.