Energy Converter
Joules to calories
Energy Converter
Convert between energy measurement units
Converted Energy
About Energy Converter
The Energy Converter helps you convert between different energy units including joules, calories, kilocalories, watt-hours, kilowatt-hours, and electronvolts. Perfect for physics students, nutrition tracking, electrical engineering, and everyday energy calculations.
Understanding energy units is essential for calculating electricity bills (kWh), food energy (calories/kcal), mechanical work (joules), and particle physics (electronvolts).
How to Use This Energy Converter
Step 1: Enter the numeric value you want to convert.
Step 2: Select the from unit (e.g., Joule, Calorie, kWh).
Step 3: Select the to unit you want to convert to.
Step 4: Click "Convert" to see the converted value.
Step 5: Use the swap button (🔄) to quickly reverse the units.
Step 6: Click Reset to clear all inputs and start a new conversion.
Why Use an Energy Converter?
✓ Electricity Bill Calculation
Convert appliance wattage to kWh to understand your electricity consumption and monthly bills.
✓ Nutrition Tracking
Convert food calories (kcal) to joules or kilojoules for scientific tracking or international food labels.
✓ Physics & Engineering
Convert between joules, electronvolts, and other units for physics calculations, thermodynamics, and mechanical work.
✓ Energy Efficiency
Compare energy consumption across different devices and systems using consistent units.
Energy Units Explained
Joule (J)
SI unit of energy. The energy required to apply 1 newton of force over 1 meter. 4,184 J = 1 food Calorie (kcal).
Calorie (cal)
Energy to heat 1g water by 1°C. 1 cal = 4.184 J. Food Calories (capital C) = 1 kcal = 1,000 cal.
Watt-hour (Wh)
Energy used by 1 watt for 1 hour. 1 Wh = 3,600 J. Electricity bills use kWh (1,000 Wh).
Electronvolt (eV)
Energy gained by an electron accelerated through 1 volt. Used in particle physics. 1 eV = 1.602 × 10⁻¹⁹ J.
Real-World Energy Examples
| Activity/Device | Energy | In Other Units |
|---|---|---|
| LED bulb (10W for 1 hour) | 36,000 J | 0.01 kWh, 8,604 cal |
| Apple (medium) | 305,000 J | 72,900 cal, 73 kcal |
| Running (30 min) | 1,256,000 J | 300 kcal, 1.256 MJ |
| AC (1.5 kW for 1 hour) | 5,400,000 J | 1.5 kWh, 1,290 kcal |
Energy Conversion Formulas
| From | To | Formula |
|---|---|---|
| Joule | Calorie | ÷ 4.184 |
| Calorie | Joule | × 4.184 |
| kWh | Joule | × 3,600,000 |
| kWh | kcal | × 860 |
| eV | Joule | × 1.602 × 10⁻¹⁹ |
Common Energy Conversions
| From | To | Multiply By |
|---|---|---|
| Joule | Calorie | 0.239006 |
| Calorie | Joule | 4.184 |
| kWh | Joule | 3,600,000 |
| kcal | kJ | 4.184 |
Frequently Asked Questions
1 calorie = 4.184 joules. Divide joules by 4.184. Example: 100 J ÷ 4.184 = 23.9 calories. Food calories (kcal) are 1000x larger: 1 kcal = 4184 J.
1 kilocalorie (kcal) = 1,000 calories. Food labels use Calories (capital C) which actually means kilocalories. 1 food Calorie = 1 kcal = 4,184 joules.
Watt-hour (Wh) is energy used by 1 watt for 1 hour. 1 Wh = 3,600 joules. Kilowatt-hour (kWh) is used for electricity bills: 1 kWh = 3.6 million joules.
1 kWh = 3,600,000 joules (3.6 × 10⁶ J). This is the standard unit for electrical energy consumption.
1 kJ = 1,000 J. To convert J to kJ: divide by 1,000. To convert kJ to J: multiply by 1,000. Example: 5,000 J = 5 kJ. 2.5 kJ = 2,500 J.
Energy = Power × Time. Power (watts) × Time (seconds) = Energy (joules). Example: 100W bulb × 3,600 seconds (1 hour) = 360,000 J = 0.1 kWh.
1 calorie (cal) = 4.184 joules (J). This is the standard conversion factor based on the specific heat capacity of water. 1 kilocalorie (kcal) = 4,184 J.
Watt (W) is power (rate of energy use). Watt-hour (Wh) is total energy used. Example: 60W bulb running for 2 hours consumes 120 Wh = 0.12 kWh.
Efficiency (%) = (Output Energy ÷ Input Energy) × 100. Example: Motor with 1,000 J input produces 800 J output = 80% efficiency. Our converter helps with unit consistency.
Energy per hour: LED bulb (10W = 0.01 kWh), Laptop (50W = 0.05 kWh), AC (1,500W = 1.5 kWh), Refrigerator (150W = 0.15 kWh), Microwave (1,000W = 1 kWh).