Kilowatt-hours to joules
Multiply kilowatt-hours by 3,600,000 to get joules.
5 kWh = 18,000,000 J
How to convert kilowatt-hours to joules
The joule is the SI unit of energy, one newton-metre (one watt for one second). The kilowatt-hour is one kilowatt for one hour, exactly 3.6 megajoules — the electricity billing unit.
Worked example — 5 kWh: 5 × 3,600,000 = 18,000,000 J.
Kilowatt-hours to joules table
| Kilowatt-hours | Joules |
|---|---|
| 0.1 kWh | 360,000 J |
| 0.5 kWh | 1,800,000 J |
| 1 kWh | 3,600,000 J |
| 2 kWh | 7,200,000 J |
| 5 kWh | 18,000,000 J |
| 10 kWh | 36,000,000 J |
| 20 kWh | 72,000,000 J |
| 50 kWh | 180,000,000 J |
| 100 kWh | 360,000,000 J |
Reverse and related
About kilowatt-hours and joules
Kilowatt-hour (kWh)
1 kWh = 3,600,000 JDefinition. One kilowatt for one hour, exactly 3.6 megajoules — the electricity billing unit
History and origin
The kilowatt-hour is the energy of one kilowatt sustained for one hour, exactly 3.6 megajoules. It became the standard way to bill electricity as power grids spread.
Current use
Kilowatt-hours are the unit on electricity bills and describe the capacity of batteries, including electric-vehicle packs.
Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)
Joule (J)
1 J = 0.000000277778 kWhDefinition. The SI unit of energy, one newton-metre (one watt for one second)
History and origin
The joule is the SI unit of energy, named after James Prescott Joule, who showed in the 1840s that heat and mechanical work are equivalent. It is the work done by one newton acting over one metre.
Current use
Joules are the standard energy unit in physics and appear on appliance and equipment ratings.
Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)
Where people use this
Kilowatt-hours: electricity bills, EV batteries. Joules: physics, appliance ratings. 1 kWh is exactly 3.6 million joules.
Every value is carried to full double precision; the display is rounded.
Both units are defined in NIST SP 811, Appendix B; ISO 80000-5 (energy).
Questions people ask
How many joules in a kWh?
One kilowatt-hour is exactly 3.6 million joules (3.6 MJ).
How many joules is 2 kWh?
2 kWh is 7.2 million joules.
Why is electricity billed in kWh?
A kWh is one kilowatt used for one hour, a convenient size for household energy.