Energy Converter
Convert between Joules, Calories, Watt-hours, and BTUs.
Enter a value to see the conversion result
Understanding Energy Conversion
Energy measures the capacity to do work or produce heat. The joule is the SI unit, while calories are used in nutrition, and kilowatt-hours measure electrical energy consumption.
| Unit Type | Unit Name | Value in Joules (J) |
|---|---|---|
| Metric | Joule (J) | 1 J |
| Metric | Kilojoule (kJ) | 1,000 J |
| Metric | Megajoule (MJ) | 1,000,000 J |
| Nutrition | Calorie (cal) | 4.184 J |
| Nutrition | Kilocalorie (kcal) | 4,184 J |
| Electrical | Watt-hour (Wh) | 3,600 J |
| Electrical | Kilowatt-hour (kWh) | 3,600,000 J |
| Imperial | BTU | 1,055.06 J |
| Physics | Electron Volt (eV) | 1.602×10⁻¹⁹ J |
Conversion Tip
Energy measures the capacity to do work. The joule is the SI unit, while calories and kilowatt-hours are common in nutrition and electricity.
Quick Reference
- 1 kilojoule = 1,000 joules
- 1 calorie = 4.184 joules
- 1 kilocalorie (kcal) = 4,184 joules
- 1 kilowatt-hour = 3.6 megajoules
- 1 BTU = 1,055.06 joules
- 1 electron volt = 1.602×10⁻¹⁹ joules
- 1 watt-hour = 3,600 joules
- 1 food calorie = 1 kilocalorie
Energy Converter Guide
Convert energy between joules, calories, watt-hours, kilowatt-hours, BTUs, and other units used in physics, engineering, electricity, and nutrition.
Choose the right context
Food energy is often expressed in kilocalories, electricity in watt-hours or kilowatt-hours, and mechanical or scientific work in joules. Confirm the context before interpreting the converted result.
Check prefixes
Prefixes such as kilo, mega, and milli change the scale by large factors. Review both the input and output units carefully before using the result in a report or calculation.