Energy Converter

Convert between different energy units including joules, calories, kilowatt-hours, and more.

Energy Converter

Common Energy Converter Formulas

  • 1 kilojoule = 1000 joules
  • 1 calorie ≈ 4.184 joules
  • 1 kilowatt-hour = 3,600,000 joules
  • 1 BTU ≈ 1,055.06 joules

Common Energy Converter References

  • Average Lightning Strike: 1 GJ
  • Daily Household Energy Use: 10-30 kWh
  • Smartphone Battery: 10-15 Wh
  • Daily Food Energy: 8400 kJ
  • Atomic Energy Level: 10⁻¹⁹ J
  • Sun's Energy Output: 3.8×10²⁶ W

What is Energy Conversion?

Energy conversion involves converting measurements of work or heat capacity from one unit to another. Energy is fundamental to physics, nutrition, electricity billing, and environmental science. Different fields use different units - joules in physics, calories in nutrition, kilowatt-hours for electricity, and BTUs for heating. Our energy converter makes these conversions simple and accurate.

Common Energy Units Explained

Joule (J)

The SI unit of energy. One joule is the energy needed to lift a small apple one meter. Used in physics and engineering calculations.

Calorie (cal)

The energy needed to raise 1 gram of water by 1°C. Food calories (kcal) are actually kilocalories. One food Calorie = 1,000 calories = 4,184 joules.

Kilowatt-hour (kWh)

Common for electricity billing. One kWh equals 3.6 million joules. A typical US household uses about 900 kWh per month.

BTU

British Thermal Unit. Common in the US for heating and cooling. One BTU ≈ 1,055 joules. Used for rating furnaces and air conditioners.

When to Use This Converter

Our energy converter is valuable for nutritionists calculating dietary energy, homeowners understanding electricity bills, engineers designing energy systems, students studying physics, and anyone comparing energy consumption or costs across different measurement systems.

Frequently Asked Questions

What is the difference between calories and Calories?

A lowercase "calorie" (cal) is the scientific calorie. An uppercase "Calorie" (Cal or kcal) used in nutrition equals 1,000 calories. Food labels use Calories (kcal).

How much energy is in one kWh?

One kilowatt-hour equals 3,600,000 joules, about 860 food Calories, or 3,412 BTUs. It can power a 100W light bulb for 10 hours.