1 kWh (kilowatt-hour) is equal to 3,600,000 joules (3.6 × 10⁶ J or 3.6 MJ). The kilowatt-hour is the commercial unit of electrical energy. It represents the energy consumed when a device with a power of 1 kilowatt operates continuously for 1 hour.
1 kWh = 3,600,000 joules (3.6 × 10⁶ J).
1 kWh = 3.6 MJ (megajoules).
kWh is the commercial unit of electrical energy used for electricity billing.
1 kWh = 1000 Wh (watt-hours).
Derivation: 1 kW × 1 hour = 1000 W × 3600 s = 3,600,000 J.
1 unit of electricity on a bill equals 1 kWh.
Energy formula: E (kWh) = Power (kW) × Time (h).
Step-by-step derivation:
1 kWh = 1 kilowatt × 1 hour = 1000 watts × 3600 seconds = 1000 J/s × 3600 s = 3,600,000 J = 3.6 × 10⁶ J = 3.6 MJ
Key relations used:
| Unit | Equivalent |
|---|---|
| Joules (J) | 3,600,000 J |
| Megajoules (MJ) | 3.6 MJ |
| Calories (cal) | 860,421 cal |
| BTU | 3412.14 BTU |
| Watt-hours (Wh) | 1000 Wh |
Note: 1 unit of electricity on your electricity bill = 1 kWh
How to calculate energy consumption:
Formula: Energy (kWh) = Power (kW) × Time (hours)
Examples:
Electricity bills charge per kWh (called a 'unit'), making kWh the most important practical unit of energy.
1 kWh (kilowatt-hour) is equal to 3,600,000 joules (3.6 × 10⁶ J or 3.6 MJ). This is derived as: 1 kW × 1 h = 1000 J/s × 3600 s = 3,600,000 J.
A kilowatt-hour (kWh) is the commercial unit of electrical energy. It is the energy consumed when an electrical device of power 1 kilowatt (1000 watts) operates continuously for 1 hour. It equals 3.6 × 10⁶ joules.
1 kWh = 1 kilowatt × 1 hour = 1000 W × 3600 s = 1000 J/s × 3600 s = 3,600,000 J = 3.6 MJ.
kW (kilowatt) is a unit of power — it measures the rate of energy consumption. kWh (kilowatt-hour) is a unit of energy — it measures the total energy consumed. A 2 kW appliance running for 3 hours consumes 6 kWh of energy.
1 MJ (megajoule) = 1,000,000 J. Since 1 kWh = 3,600,000 J, we get: 1 MJ = 1/3.6 kWh ≈ 0.2778 kWh. Conversely, 1 kWh = 3.6 MJ.
Difference Between Half Wave and Full Wave Rectifier
Learn the difference between a Half Wave and a Full Wave Rectifier. Understand how P-N junction diodes convert AC to DC current in electronics.
Heating Effect of Electric Current (Joule's Law)
Learn about the Heating Effect of Electric Current. Understand Joule's Law of Heating, its formula (H = I²Rt), and real-life applications like heaters and irons.
Difference Between Heat and Temperature
Learn the exact scientific difference between Heat and Temperature. Understand why heat is total energy (Joules) while temperature is average energy (Kelvin).
What is a Horseshoe Magnet?
Learn what a horseshoe magnet is. Understand why it is shaped like a U, why it is stronger than a bar magnet, and its common uses.
Structure and Diagram of the Human Eye (Class 10 Physics)
Learn the complete structure of the human eye for Class 10 Physics. Understand the functions of the Retina, Cornea, Lens, and Pupil in simple language.
Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.