Kilojoules (kJ) and kilowatt-hours (kWh) are both ways to measure energy. You’ll often see kWh on your electricity bill, as it measures how much electrical energy you’ve used. This article explains how to convert from kJ to kWh.
What is a Kilojoule (kJ)?
A kilojoule (kJ) is a unit of energy. Specifically, it’s equal to 1,000 joules (J). The joule is the standard unit of energy in the International System of Units (SI).
You’ll often see kilojoules used to measure heat, work, and other forms of energy. In other words, it’s a common way to quantify how much “oomph” something has. It’s related to other energy units like calories, but we’ll stick to kJ and kWh for this article.
Understanding Kilowatt-hours (kWh)
A kilowatt-hour (kWh) is a unit of energy that describes how much energy you’d use if you ran a 1,000-watt appliance for one hour. Think of a powerful space heater or maybe a hair dryer on high heat.
Electric companies usually measure your electrical consumption in kilowatt-hours, and that’s how they calculate your bill.
(Kilowatt-hours can also be converted into other energy units, but we won’t go into that here.)
The conversion formula: kJ to kWh
Ready to do some converting? Here’s what you need to know:
The formula is: kWh = kJ ÷ 3,600.
In other words, one kWh is the same as 3,600 kJ. If you’re going the other direction, 1 kJ = 0.0002777778 kWh.
The number 3,600 is the number of seconds in an hour (3,600 seconds = 1 hour), and it represents the relationship between watts, joules, and time.
Here’s an example: Let’s convert 5,000 kJ to kWh: kWh = (5,000 kJ ÷ 3,600) = 1.388889 kWh.
Practical Applications and Examples
Converting between kilojoules and kilowatt-hours is useful in a wide range of situations. For instance, you might want to calculate the energy used by your appliances, or you might be comparing different sources of energy to see which is more efficient.
Here are a couple of examples:
- To convert 10,000 kJ to kWh: kWh = (10,000 kJ / 3600) = 2.77778 kWh
- To convert 1,800 kJ to kWh: kWh = (1,800 kJ / 3600) = 0.5 kWh
You can also convert from kWh back to kJ using this formula: kJ = kWh 3,600.
Wrapping Up
Kilojoules (kJ) and kilowatt-hours (kWh) are both ways of measuring energy, and they’re related by a simple conversion factor.
Knowing how to convert between kJ and kWh is useful in many fields.
So, use the formula and examples provided here to help you make accurate conversions between these two common energy units.