Kilowatt-Hours to Joules
One kilowatt-hour equals 3600000 joules.
Joules = kilowatt-hours × 3600000
Energy Converter
Common Conversions
Energy Examples
Household Energy
- • Average home daily use: ~30 kWh
- • LED bulb (10W, 1 hour): 36 kJ
- • Microwave (1000W, 2 min): 120 kJ
- • Electric car (100 miles): ~30 kWh
Food Energy
- • Apple: ~350 kJ (80 kcal)
- • Slice of bread: ~315 kJ (75 kcal)
- • Can of soda: ~590 kJ (140 kcal)
- • Daily intake: ~8400 kJ (2000 kcal)
Energy Unit Reference
Scientific Units
- • Joule (J): SI base unit of energy
- • Calorie (cal): Energy to heat 1g water by 1°C
- • Electron Volt (eV): Atomic scale energy
- • Erg: CGS unit (very small)
Practical Units
- • kWh: Electrical energy billing
- • BTU: Heating/cooling systems
- • Therm: Natural gas billing
- • kcal: Food energy (Calories)
Kilowatt-Hours to Joules Conversion Table
| kWh | J |
|---|---|
| 0.1 | 360000 |
| 0.5 | 1800000 |
| 1 | 3600000 |
| 2 | 7200000 |
| 3 | 10800000 |
| 5 | 18000000 |
| 10 | 36000000 |
| 15 | 54000000 |
| 20 | 72000000 |
| 25 | 90000000 |
| 50 | 180000000 |
| 100 | 360000000 |
| 250 | 900000000 |
| 500 | 1800000000 |
| 1000 | 3600000000 |
About This Conversion
Kilowatt-hours to joules multiplies by 3,600,000. A kilowatt-hour is one kilowatt sustained for one hour, and since a watt is a joule per second, an hour of it is 1,000 × 3,600 joules.
This is the unit electricity is billed in, so it is the bridge between a utility bill and any physics or engineering calculation. A 2 kW heater run for three hours uses 6 kWh, which is 21.6 megajoules, and at a tariff of 25 cents per kWh that is 1.50 in whatever currency the bill is in.
Frequently Asked Questions
How many joules is 1 kWh?
One kilowatt-hour is 3,600,000 joules, or 3.6 megajoules.
How many joules is a watt-hour?
One watt-hour is 3,600 joules.
How much energy does a 2 kW heater use in 3 hours?
6 kWh, which is 21.6 megajoules.
Why is a kilowatt-hour not a kilowatt?
A kilowatt is a rate of energy use; a kilowatt-hour is the amount used when that rate runs for one hour.
Worth Knowing
Calorie vs Kilocalorie
One food Calorie is one kilocalorie, equal to 1,000 small calories or 4,184 joules.