Energy Converter
Convert between joules, calories, kWh, and BTU.
⚡ Food "Calories" are actually kilocalories (kcal). 1 kcal = 4.184 kJ.
What Is This Tool?
This tool converts between energy units: joules, calories, kilowatt-hours, BTU, and electron-volts. Energy appears in nutrition, electricity, physics, and heating.
The Calorie Confusion
Food labels use Calories with a capital C, which actually means kilocalories(kcal). One food Calorie = 1,000 small calories = 4,184 joules. So a "200 Calorie" snack contains 200,000 small calories — but everyone means kcal when discussing food.
Key Conversions
- 1 kilocalorie (kcal) = 4.184 kilojoules (kJ)
- 1 kilowatt-hour (kWh) = 3,600,000 joules = 860.4 kcal
- 1 BTU ≈ 1,055 joules (energy to heat 1 lb of water by 1°F)
- 1 electron-volt (eV) = 1.602 × 10⁻¹⁹ joules (subatomic scale)
Real-World Energy
- Banana: ~105 kcal = 439 kJ
- 1 kWh of electricity ≈ 860 kcal
- Running a 60W bulb for 1 hour: 216,000 joules
- Average daily human diet: 2,000 kcal = 8,368 kJ
Frequently Asked Questions
Why does my electric bill use kWh?
A watt is joules per second, so multiplying by hours gives total energy. 1 kWh = using 1,000 watts for 1 hour. It's a convenient unit for household electricity.
About the Energy Converter
The Energy Converter converts energy converterfrom one unit to another using the exact internationally defined conversion factors. Type a value, choose your source and target units, and the converted result is shown instantly — no waiting, no page reload.
Manual conversion is error-prone because it means memorizing ratios (how many feet in a meter, how many pints in a liter). This tool removes that friction: the conversion factor is built in, and the math is done to full precision with no rounding until the final displayed number.
How to Use This Tool
- Enter the value you want to convert in the input field.
- Select the unit you are converting from.
- Select the unit you want to convert to.
- The converted value appears instantly. Adjust either unit to compare across the board.
- Copy the result if you need it elsewhere. Your input is never sent anywhere.
Why Use an Online Converter?
Browser-based tools like this one have a few real advantages over installed software or manual methods:
- No installation. It opens instantly in any browser, on any operating system.
- Private by default. Everything runs locally, so your data stays on your device.
- Always up to date.There's nothing to update — you always get the latest version when you load the page.
- Free and unlimited. Use it as often as you like, with no account and no caps.
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