Convert Joules to Kilowatt-Hours
Convert Joules (J) to Kilowatt-Hours (kWh) instantly and accurately.
Conversion Formula
kWh = J × 2.777777778e-7
About Joules
The joule (J) is the SI unit of energy, defined as one newton acting through one metre (1 J = 1 N·m = 1 kg·m²/s²). Named after James Prescott Joule, whose 1840s paddle-wheel experiments established the mechanical equivalent of heat (~4.15 J = 1 calorie). One joule is modest: it lifts a 100 g apple by 1 m, heats 0.239 mL of water by 1°C, or powers a 1 W LED for 1 second. Daily adult resting metabolism is ~6-9 MJ. 1 J = 1 W·s = 0.23901 cal = 9.4782 × 10⁻⁴ BTU = 2.7778 × 10⁻⁷ kWh.
About Kilowatt-Hours
A kilowatt-hour (kWh) is the energy consumed by 1 kW for one hour - exactly 3,600,000 J = 3.6 MJ. All domestic electricity meters bill in kWh. Appliance benchmarks: fridge 180-250 kWh/year; washing machine 0.5-2.0 kWh/cycle; air conditioner 1-3 kWh/h. EVs consume 13-25 kWh/100 km; the Lucid Air achieves ~15.9 kWh/100 km (WLTP). Producing 1 tonne of primary aluminium requires ~13,000-15,000 kWh. Global electricity generation is ~29,165 TWh ≈ 2.9 × 10¹³ kWh/year. 1 kWh = 3.6 MJ = 3,412.1 BTU = 859.85 kcal.
Quick Reference Table
| Joules (J) | Kilowatt-Hours (kWh) |
|---|---|
| 1 J | 2.778 × 10-7 kWh |
| 2 J | 5.556 × 10-7 kWh |
| 5 J | 1.389 × 10-6 kWh |
| 10 J | 2.778 × 10-6 kWh |
| 25 J | 6.944 × 10-6 kWh |
| 50 J | 1.389 × 10-5 kWh |
| 100 J | 2.778 × 10-5 kWh |