โก Energy
Convert energy units free: joule, calorie, kilowatt-hour, BTU, kilojoule. For nutrition, electricity and engineering.
โก Energy
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About the Energy Tool
Energy appears in several domains with entirely different conventional units. Nutrition labels use calories or kilojoules, electricity bills use kilowatt-hours, heating and cooling equipment is rated in BTU, and physics uses joules.
They all measure the same quantity, which makes conversion genuinely illuminating โ a food calorie is about 4184 joules, and an air conditioner rated at 12,000 BTU per hour is drawing roughly 3.5 kilowatts of cooling capacity. This converter handles all of them instantly in your browser.
How to Use Energy
- Enter the energy value.
- Select the source unit.
- Select the target unit.
- Read the converted result.
When to Use This Tool
- Converting nutrition label values between calories and kilojoules
- Understanding electricity consumption in different units
- Comparing air conditioner or heater ratings across markets
- Converting engineering energy figures for calculations
- Relating fuel energy content to electrical equivalents
Things Worth Knowing
- A food Calorie with a capital C is a kilocalorie โ 1000 small calories. Nutrition labels always mean kilocalories.
- One kilowatt-hour is 3.6 million joules.
- BTU is the energy to raise one pound of water by one degree Fahrenheit, roughly 1055 joules.
Quick Facts
| Tool name | Energy |
| Category | Unit Converters |
| Price | Free โ no account, no trial, no watermark |
| Where it runs | Entirely in your browser (client-side) |
| Files uploaded | None โ your data never leaves your device |
| File size limit | None imposed; limited only by device memory |
| Works offline | Yes, once the page has loaded |
| Platforms | Windows, macOS, Linux, Android, iOS |
Frequently Asked Questions
Is a food calorie the same as a physics calorie?
No, and this causes constant confusion. A nutritional Calorie is a kilocalorie โ 1000 physics calories, or about 4184 joules. A 500-Calorie meal contains around 2.1 million joules.
How many joules in a kilowatt-hour?
Exactly 3,600,000. A kilowatt is 1000 joules per second, and an hour is 3600 seconds, so the product is 3.6 megajoules.
What does BTU mean on an air conditioner?
It rates cooling capacity per hour. A 12,000 BTU/h unit removes about 3.5 kW of heat, which is why 12,000 BTU is often described as one ton of cooling.
Why do nutrition labels show both kJ and kcal?
Because kilojoules are the SI standard required in many jurisdictions, while kilocalories remain the familiar figure for consumers. Both express the same energy content.