Convert joules to kJ
Input the number of joules you want to convert to kilojoules.
How to Convert Joules to Kilojoules
The joule and kilojoule are both units of energy. By definition, 1 kilojoule equals exactly 1000 joules. This means to convert joules to kilojoules, you divide by 1000.
Formula
Step-by-Step Example
Convert 5 J to kilojoules:
We need to convert joules to kilojoules
Since 1 kJ = 1000 J, divide by 1000
5 ÷ 1000 = 0.005
5 J = 0.005 kJ
Joule to Kilojoule Conversion Table
Quick reference table for common joule to kilojoule conversions. Click any value for detailed calculation.
| Joules (J) | Kilojoules (kJ) |
|---|---|
| 0.1 J | 0.0001 kJ |
| 0.5 J | 0.0005 kJ |
| 1 J | 0.001 kJ |
| 2 J | 0.002 kJ |
| 5 J | 0.005 kJ |
| 10 J | 0.01 kJ |
| 25 J | 0.025 kJ |
| 50 J | 0.05 kJ |
| 100 J | 0.1 kJ |
About These Units
Joule (J)
The joule (J) is the SI unit of energy equal to one watt-second or one newton-meter. Joules measure work, heat, and electrical energy. One joule equals approximately 0.239 calories. Lifting a 100g apple one meter requires about 1 joule. Named after physicist James Prescott Joule.
Kilojoule (kJ)
A kilojoule (kJ) equals 1,000 joules or approximately 239 calories. Kilojoules measure food energy on nutrition labels in Australia, Europe, and many countries. An average adult needs 8,400-10,000 kJ daily. One kJ equals approximately 0.239 kcal.
Frequently Asked Questions
How do I convert joules to kilojoules?
To convert joules to kilojoules, divide the value by 1000. For example, 10 J = 0.01 kJ.
How many kilojoules are in 1 joule?
1 joule equals 0.001 kilojoules.
What is the formula for joules to kilojoules?
The formula is: kJ = J ÷ 1000.