Energy converter

Joules, calories and kilowatt hours

Energy converter

To0.239006

1 J = 0.23900574 cal

About the Energy converter

Energy appears as joules in physics, calories in nutrition, and kilowatt hours on electricity bills. All measure the same thing — the capacity to do work — just at very different scales.

Everything converts through the joule. One (small) calorie is exactly 4.184 joules, a food Calorie (kcal) is 4,184 joules, and one kilowatt hour is exactly 3.6 million joules.

Common use cases

  • Comparing food energy (kcal) with exercise burn
  • Understanding electricity bills in kWh
  • Physics and engineering calculations in joules
  • Battery capacity comparisons in watt hours

Frequently asked questions

A food Calorie (capital C) is actually a kilocalorie — 1,000 small calories. Nutrition labels always mean kilocalories.