Energy Converter
Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours and BTU.
Result4.184
Popular Energy conversions
Kilocalories → Kilojoules
1 kcal = 4.184 kJ
Kilojoules → Kilocalories
1 kJ = 0.23900574 kcal
Kilowatt-hours → Kilojoules
1 kWh = 3,600 kJ
Kilowatt-hours → Joules
1 kWh = 3,600,000 J
Calories → Joules
1 cal = 4.184 J
BTU → Kilojoules
1 BTU = 1.05505585 kJ
Joules → Calories
1 J = 0.23900574 cal
Kilocalories → Calories
1 kcal = 1,000 cal
About energy units
Energy is the capacity to do work, and heat, electricity and food energy are all forms of it. The joule is the SI unit. Nutrition uses the (kilo)calorie — one kilocalorie is 4.184 kilojoules, and food labels’ "Calories" are really kilocalories. Electricity is billed in kilowatt-hours, the energy of one kilowatt used for one hour (3.6 million joules).
The BTU (British thermal unit) is common for heating and air-conditioning ratings.
Handy Energy reference points
- 1 kcal = 4.184 kJKilocalorie to kilojoules
- 1 kWh = 3.6 MJKilowatt-hour to megajoules
- ≈ 95 kcalEnergy in a medium apple
- 1 BTU ≈ 1.055 kJBTU to kilojoules
- 1 kWh = 860 kcalKilowatt-hour in kilocalories
Supported Energy units
- Joules (J) — The SI unit of energy.
- Kilojoules (kJ) — One thousand joules.
- Calories (cal) — A calorie, 4.184 joules.
- Kilocalories (kcal) — A kilocalorie (food "Calorie"), 4,184 joules.
- Watt-hours (Wh) — A watt-hour, 3,600 joules.
- Kilowatt-hours (kWh) — A kilowatt-hour, 3.6 million joules; the electricity billing unit.
- BTU (BTU) — A British thermal unit, about 1,055 joules.
This tool is provided for general information only. Verify important figures independently. · Last reviewed: August 25, 2026