Energy Converter
Joule
Definition: The joule (symbol: J) is the base unit of energy in the International System of Units (SI). It is defined as the work done by a force of one newton acting through a distance of one meter.
History/origin: The unit is named in honor of the English physicist James Prescott Joule, who established the relationship between heat and mechanical work in the mid-19th century.
Current use: Joules are the standard unit used in physics and engineering to measure work, heat, and electrical energy.
Kilojoule
Definition: A kilojoule (symbol: kJ) is a multiple of the joule, equal to one thousand (1,000) joules.
History/origin: Following the SI metric system prefix rules, the kilojoule was adopted to express larger amounts of energy that would otherwise require cumbersome numbers if written in joules.
Current use: Kilojoules are widely used to measure the nutritional energy value of food in countries outside the United States, and to measure the energy output of engines and heavy machinery.
Joule to Kilojoule Conversion Table
| Joule [j] | Kilojoule [kj] |
|---|---|
| 0.01 j | 0.00001 kj |
| 0.1 j | 0.0001 kj |
| 1 j | 0.001 kj |
| 2 j | 0.002 kj |
| 3 j | 0.003 kj |
| 5 j | 0.005 kj |
| 10 j | 0.01 kj |
| 20 j | 0.02 kj |
| 50 j | 0.05 kj |
| 100 j | 0.1 kj |
| 1000 j | 1 kj |
How to Convert Joule to Kilojoule
1 j = 0.001 kj
1 kj = 1000 j
Example: convert 15 j to kj:
15 j = 15 × 0.001 kj = 0.015 kj
Did You Know?
- Did you know? One Joule is roughly the amount of energy required to lift a small apple (100 grams) one meter straight up into the air!
- In many countries like Australia and parts of Europe, food energy is officially listed in Kilojoules (kJ) rather than Calories. One kcal is roughly equal to 4.18 kJ.