Convert kilojoules to joules
Converting kilojoules to joules is a common energy task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 kJ equals 1,000 J, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert kilojoules to joules
To convert kilojoules to joules, multiply the number of kilojoules by 1,000. For example, 10 kJ × 1,000 = 10,000 J.
J = kJ × 1,000
- Write down the value in kilojoules you want to convert.
- Multiply it by 1,000 (the exact kJ→J factor).
- The result is your value in joules. Check it below with the converter or the table.
Conversion table
Common values of kilojoules and their equivalents in joules:
| kJ | J |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 4 | 4,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 20 | 20,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
About these units
Kilojoule (kJ). A kilojoule is 1,000 joules, the practical unit for food energy in Australia and Europe and for mechanical work. One kilocalorie equals 4.184 kilojoules.
Joule (J). The joule is the SI unit of energy: the work done by one newton acting over one meter. Food labels in most countries, physics and engineering use joules.
Frequently asked questions
How do I convert kilojoules to joules?
To convert kilojoules to joules, multiply the number of kilojoules by 1,000. For example, 10 kJ × 1,000 = 10,000 J. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many joules are in 1 kilojoule?
1 kJ = 1,000 J. That is the fixed relationship used by this converter and by international standards.
How many kilojoules are in 1 joule?
1 J = 0.001 kJ. If you are converting in the opposite direction, use our Joule to Kilojoule converter for the dedicated table and FAQ.
Is the kilojoules to joules conversion exact?
Yes. Both units are defined by international agreement, so the factor of 1,000 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is kilojoule used for?
A kilojoule is 1,000 joules, the practical unit for food energy in Australia and Europe and for mechanical work. One kilocalorie equals 4.184 kilojoules.