kW to kJ Calculator
Convert kW to kJ from the time in seconds: E = P × t. One kW is 1,000 joules per second. Formula, worked example and a table of typical values.
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Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.
Open in the calculator with these values
Formula
Worked example
| Input | Value |
|---|---|
| Power | 2 kW |
| Time | 60 s |
- E = P × t = 2,000 W × 60 s = 120,000 J
- In other units: 0.033333 kWh = 0.12 MJ; 2 kW; 0.016667 h
Typical values
| Time (s) | Energy (kJ) |
|---|---|
| 1 | 2 |
| 10 | 20 |
| 60 | 120 |
| 600 | 1,200 |
| 3,600 | 7,200 |
Other inputs are the same as in the worked example above.
Assumptions
- Constant power over the whole time
- Real (active) power, not apparent power
Change any unit to read the answer in kWh, Wh, kJ or MJ. For a varying load the result is the average power or the total energy, not the instantaneous value. For a cost, use Energy and Cost.
Frequently asked questions
How do I convert kW to kJ?
E = P × t (1 W × 1 s = 1 J, 1 kW × 1 h = 1 kWh = 3.6 MJ). Worked example: Power 2 kW, time 60 s gives 120 kJ.
What do I need to enter?
Enter power, energy and time. Leave blank the value you want to find, and the form solves for it. Change the unit of a value with its selector and the result stays the same.
How are watts, kW, joules and kJ related?
One watt is one joule per second, so energy in joules is power in watts multiplied by time in seconds. One kW is 1,000 W and one kJ is 1,000 J. Joules measure energy and watts measure power, so a time is always needed.
How accurate are the results?
Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. Check design values against the standard and the equipment data you work to.
Related
Next steps in a design: kWh to kWEnergy ConsumptionEnergy Unit Converter
Opposite direction: kJ to kW
Also see: Watts to Wh Wh to Watts Amps to kW kW to Amps
Formula guides: Energy ConverterJ to kJ ConverterkJ to J Converter
All 78 conversionsWatts, Joules, kWh and Time (any two) in Elecmetric