Energy Converter
Convert between joules, calories, watt-hours, and BTU.
About this converter
Energy shows up in wildly different units depending on the field — joules in physics, calories on food labels, kilowatt-hours on electric bills, and BTU for heating/cooling systems. This converts between all of them.
Frequently asked questions
- Is a food "Calorie" the same as a science "calorie"?
- No — a food Calorie (capital C, sometimes written kcal) is actually 1,000 small calories. This converter uses the small calorie as its "cal" unit; for food-label Calories, use the kcal option instead.