⚡ Energy Unit Converter
Convert between Joules, Calories, Kilowatt-hours, BTUs, Electronvolts, Therms, and more. Perfect for physics, nutrition, engineering, and electricity calculations.
1 kWh =
3.6 MJ
3,600,000 Joules
1 kcal =
4.184 kJ
Food calorie
1 BTU =
1055 J
British Thermal Unit
1 eV =
1.6×10⁻¹⁹ J
Electronvolt
Energy Converter
⚡ Converted Energy
1 J = 0.000239 kcal
Energy Equivalence
💡 1 kWh powers a 100W bulb for 10 hours
🍎 1 kcal ≈ energy to walk 20 minutes
🔥 1 BTU ≈ heat from a birthday match
📚 Energy Conversion Facts
- 1 Joule (J) = 0.239 calories
- 1 Calorie (kcal) = 4184 Joules
- 1 kWh = 3.6 million Joules
- 1 BTU = 1055 Joules
- 1 eV = 1.602 × 10⁻¹⁹ J
- 1 Therm = 29.3 kWh
🌍 Real World Energy Examples
💪 Daily Energy Needs
Average adult daily intake: 2000-2500 kcal
That's enough energy to:
- ⚡ Power a TV for 2 weeks
- 🚗 Drive an EV ~40 km
- 🏃 Run a marathon (42km)
- 💡 Light a 100W bulb for 20 hours
📊 Why Use an Energy Converter?
Energy conversion is essential in physics, nutrition, engineering, and everyday life. Whether you're calculating food calories, understanding your electricity bill, working with scientific experiments, or comparing fuel efficiency, accurate energy conversion helps you make informed decisions.
🍎 Nutrition
Food energy in calories (kcal) to joules for scientific understanding.
⚡ Electricity
Convert kWh (your electricity bill) to joules or BTUs for comparison.
🔬 Physics
Electronvolts (eV) to joules for particle physics and quantum mechanics.
❓ Frequently Asked Questions
What's the difference between calorie and Calorie?
Lowercase "calorie" (cal) = 4.184 joules. Uppercase "Calorie" (Cal) or kilocalorie (kcal) = 1000 calories = 4184 joules. Food labels use Calories (kcal). So a 200 Calorie snack actually contains 200,000 calories or 836,800 joules!
How do I calculate my electricity usage?
Your electricity bill shows kWh used. 1 kWh = using 1000 watts for 1 hour. A 100W bulb running 10 hours uses 1 kWh. Use our converter to see this in joules or BTUs. 1 kWh = 3,600,000 J = 3.6 MJ = 3,412 BTU.
What is an electronvolt (eV)?
An electronvolt is the energy gained by an electron accelerating through 1 volt of potential difference. It's tiny: 1 eV = 1.602 × 10⁻¹⁹ J. Used in particle physics, quantum mechanics, and semiconductor physics. A typical electron in an atom has energy of a few eV.
How many joules in a kilowatt-hour?
1 kilowatt-hour (kWh) = 3,600,000 joules exactly. This is because 1 watt = 1 joule/second, and 1 hour = 3600 seconds: 1000 W × 3600 s = 3,600,000 J. This is the standard unit for electricity billing.
What is a BTU and when is it used?
BTU (British Thermal Unit) is the amount of energy needed to heat 1 pound of water by 1°F. 1 BTU ≈ 1055 J. Used in heating/cooling systems, natural gas billing, and HVAC. A typical home AC has capacity of 12,000-24,000 BTU/hour.
⚠️ Disclaimer: All conversions are based on standard international definitions. For nutritional information, note that food calories (kcal) are used. For scientific applications, use exact values. Conversion factors are based on the International System of Units (SI).