What is a Kilowatt-Hour?

The kilowatt-hour equals 1,000 watt-hours (3.6 megajoules) and is the universal billing unit for residential electricity consumption around the world. A typical US household uses about 800–1,000 kWh per month; a refrigerator consumes 1–2 kWh per day, an LED bulb at 10 W for 10 hours uses 0.1 kWh, and a Tesla Model 3 has a 75 kWh battery (about 250–350 miles of range). Electric utility rates are quoted in cents per kWh — typical US residential rates are 11–25 ¢/kWh, while industrial rates are lower. The kilowatt-hour is essential in renewable-energy planning: solar panel output, wind farm production, and grid-scale storage are all rated in kWh or MWh (megawatt-hours). It relates to the watt-hour (1,000 Wh = 1 kWh), the joule (1 kWh = 3.6 MJ), the BTU (1 kWh ≈ 3,412 BTU), and the megawatt-hour (1,000 kWh = 1 MWh).

Visual reference for how the kilowatt-hour relates to other energy units. Each row links to the full converter for that pair.

• Electricity billing globally
• EV battery capacity specifications
• Home solar and battery storage

• ✓1 kWh = 3.6 MJ = 3,600,000 J.
• ✓Multiply device power (kW) × time (h) = energy (kWh).
• ✓EV "range anxiety" translates to knowing kWh available.

• ✗Confusing kWh (energy) with kW (power).
• ✗Calculating electric costs by power ignoring duration.
• ✗Using "kWh/h" — redundant; it's just kW.