Energy Converter — Joules, Calories, kWh and More
Energy is the capacity to do work. It appears in many forms — heat, electrical, chemical, kinetic — and is measured in many different units depending on the context. Our energy converter handles all common energy units for physics, nutrition, and engineering.
Key Energy Units
- Joule (J): The SI unit of energy. 1 J = energy needed to move 1 kg by 1 m² per second squared.
- Calorie (cal): The energy needed to raise 1 gram of water by 1°C. 1 cal = 4.184 J.
- Kilocalorie (kcal): What food labels call a "Calorie" (with capital C). 1 kcal = 1,000 cal = 4,184 J.
- kWh (kilowatt-hour): Used by electricity companies for billing. 1 kWh = 3,600,000 J = 3.6 MJ.
- BTU (British Thermal Unit): Used in heating/cooling systems. 1 BTU = energy needed to raise 1 pound of water by 1°F = 1,055 J.
Food & Nutrition Energy
Food energy is measured in kilocalories (kcal), commonly written as Calories (capital C) on food labels. Here is what everyday foods provide:
- 1 apple ≈ 95 kcal
- 100g cooked rice ≈ 130 kcal
- 1 egg ≈ 70 kcal
- 1 slice of bread ≈ 80 kcal
- Daily requirement for an adult ≈ 2,000–2,500 kcal
Electricity & Power Bills
1 kWh is the energy used by a 1,000-watt appliance running for 1 hour. A typical LED bulb (10W) running for 100 hours uses 1 kWh. A split AC (1.5 ton) uses about 1.5 kWh per hour.