Energy Converter

An energy converter transforms a measurement of energy from one unit to an equivalent value in another unit. Energy is the capacity to do work, and it is measured in many different units depending on the field: joules in physics and engineering, kilocalories in nutrition, kilowatt-hours in electricity billing, BTUs in HVAC and US energy, and electronvolts in particle physics. Our energy converter covers 20 units across five systems using exact, internationally recognised conversion factors, and shows a complete conversion table across all units in one click.

1. 1. Select Your Source and Target Units: Choose the energy unit you are converting from and the unit you want to convert to from the 20 available options. Use the swap button (⇄) to instantly reverse the conversion direction.
2. 2. Enter Your Value: Type the energy value you want to convert. The energy converter accepts any positive or negative number, including decimals and scientific notation values. The input label updates automatically to show the selected unit.
3. 3. View the Result and Full Conversion Table: Click Convert Energy to see the direct result plus a complete table showing your input value converted to all 20 energy units, grouped by system — SI/metric, thermal, electrical, mechanical, and atomic/physics.

• Joule (J): The SI base unit of energy. 1 J = 1 kg·m²/s² = 1 N·m = 1 W·s.
• Kilojoule (kJ): 1,000 J. Used in nutrition (food energy in many countries), chemistry, and engineering.
• Megajoule (MJ): 1,000,000 J. Used in energy statistics, natural gas billing, and large-scale engineering.
• Gigajoule (GJ): 10⁹ J. Used in national energy statistics and large industrial processes.

🔥 Thermal Energy Units:

• Calorie (cal): The thermochemical calorie: 4.184 J. The energy to raise 1 g of water by 1°C.
• Kilocalorie (kcal): 4,184 J. The "food Calorie" (capital C) used in nutrition labelling in the US and UK.
• BTU (IT): British Thermal Unit: 1,055.06 J. The energy to raise 1 lb of water by 1°F. Used in HVAC and US energy.
• Therm (US): 100,000 BTU = 105.48 MJ. Used for natural gas billing in the United States.

• Watt-hour (Wh): 3,600 J. The energy consumed by a 1-watt device running for 1 hour.
• Kilowatt-hour (kWh): 3,600,000 J. The standard unit for electricity billing worldwide.
• Megawatt-hour (MWh): 3.6 × 10⁹ J. Used for large-scale power generation and grid-level energy storage.

⚙️ Mechanical Energy Units:

• Foot-pound (ft·lbf): 1.356 J. The work done by a 1-pound force over 1 foot. Used in US engineering and torque.
• Erg: 10⁻⁷ J. The CGS unit of energy. Used in older physics literature and astrophysics.

⚛️ Atomic / Physics Units:

• Electronvolt (eV): 1.602 × 10⁻¹⁹ J. The energy gained by an electron moving through 1 volt. Used in particle physics and semiconductor physics.
• Megaelectronvolt (MeV): 1.602 × 10⁻¹³ J. Used in nuclear physics and particle accelerator energies.
• Hartree (Eₕ): 4.360 × 10⁻¹⁸ J. The atomic unit of energy used in quantum chemistry calculations.