Enter a value and pick its unit (Joules, kWh, BTU, calories, electronvolts, ergs), and the tool converts it to every other energy unit live.
1 kilowatt-hour = 3,600,000 joules (3.6 megajoules).
1 calorie (small cal) = 4.184 joules; 1 kilocalorie (food Calorie) = 4,184 joules.
A British Thermal Unit equals about 1,055.06 joules — commonly used for air conditioner and heater ratings.