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Energy Converter

Convert between energy units including Joules, calories, BTU, kWh, electronvolts, and more. Essential for physics, engineering, nutrition, and energy calculations.

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Quick Reference:
1 Joule (J) = 0.239 calories
1 calorie = 4.184 Joules
1 kWh = 3,600,000 Joules = 3.6 MJ
1 BTU = 1,055.06 Joules

All Conversions

Enter an energy value to see all conversions

Real-World Energy Examples

Apple (food energy)
335.0K J
Medium apple, ~80 calories
Banana (food energy)
439.0K J
Medium banana, ~105 calories
LED Light Bulb (1 hour)
36.0K J
10W LED bulb for 1 hour
Laptop (1 hour)
180.0K J
50W laptop for 1 hour
Electric Oven (1 hour)
7.2M J
2000W oven for 1 hour
Household (daily)
108.0M J
Average US home, ~30 kWh/day
Car Battery
1.8B J
12V, 50Ah battery, ~0.5 kWh
Lightning Bolt
5.0B J
Average lightning strike
TNT Explosion (1 kg)
4.2B J
1 kg TNT equivalent
Nuclear Bomb (1 kiloton)
4184.0B J
1 kiloton TNT equivalent

Energy conversion is fundamental to understanding physics, engineering, nutrition, and everyday life. Energy exists in many forms and can be converted between different units depending on the context. This converter helps you convert between all common energy units used in science, engineering, and daily applications.

Understanding Energy Units

Common energy units and their uses:

  • Joule (J): SI unit, used in physics and engineering worldwide
  • Calorie (cal): Used in nutrition and chemistry, 1 cal = 4.184 J
  • Kilocalorie (kcal): Food energy unit, what "Calories" on labels actually means
  • BTU: British Thermal Unit, used for heating/cooling in the US
  • kWh: Kilowatt-hour, standard unit for electricity billing
  • Electronvolt (eV): Used in atomic and particle physics
  • Foot-pound: Imperial unit for mechanical work

Energy Forms and Conversions

Forms of Energy:
• Kinetic (motion)
• Potential (stored)
• Thermal (heat)
• Electrical
• Chemical
• Nuclear
Applications:
• Physics calculations
• Nutrition labels
• Electricity bills
• Heating/cooling
• Mechanical work
• Energy efficiency

Key Energy Conversions

Common Conversions:
1 J = 0.239 cal = 0.000239 kcal
1 cal = 4.184 J
1 kcal = 4,184 J = 4.184 kJ
1 BTU = 1,055.06 J = 252 cal
1 kWh = 3,600,000 J = 860 kcal
Scientific Units:
1 eV = 1.602 × 10⁻¹⁹ J
1 ft-lb = 1.356 J
1 therm = 105,506,000 J
1 quad = 1.055 × 10¹⁸ J
1 kJ = 1,000 J

Energy in Daily Life

Energy consumption examples:

  • Food: Average adult needs ~2,000 kcal/day = 8,368,000 J = 8.37 MJ
  • Electricity: Average US home uses ~900 kWh/month = 3,240,000,000 J = 3.24 GJ
  • Transportation: Car uses ~30-40 MJ per liter of gasoline
  • Exercise: Running burns ~60-80 kcal/km = 250-335 kJ/km
  • Appliances: LED bulb (10W) uses 36,000 J/hour, laptop (50W) uses 180,000 J/hour

Note: All conversions are mathematically exact based on standard conversion factors. Energy can be converted between different forms (e.g., electrical to thermal, chemical to kinetic), but the total energy in a closed system is conserved. When converting between units, ensure you're using the correct conversion factors for your specific application.

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