Joule to Kilojoule Converter
Convert Joule (J) to Kilojoule (kJ) instantly. 1 J = 0.001 kJ.
Energy Converter
27 units available
1 J = 0.001 kJ
Formula:
kJ = J × 0.001With your value: 1 J = 0.001 kJ
How big is that?
Everyday references on a logarithmic scale, all expressed in joule so you can sanity-check the result.
Other Joule to Kilojoule conversions
Joule to Kilojoule Conversion Table
| Joule (J) | Kilojoule (kJ) |
|---|---|
| 0.5 | 0.0005 |
| 1 | 0.001 |
| 2 | 0.002 |
| 5 | 0.005 |
| 10 | 0.01 |
| 15 | 0.015 |
| 20 | 0.02 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1000 | 1 |
Kilojoule to Joule Conversion Table
| Kilojoule (kJ) | Joule (J) |
|---|---|
| 0.5 | 500 |
| 1 | 1,000 |
| 2 | 2,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 15 | 15,000 |
| 20 | 20,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1000 | 1,000,000 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Joule (J)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
Kilojoule (kJ)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
How to Convert Joule to Kilojoule
To convert from Joule (J) to Kilojoule (kJ), multiply the value by 0.001.
Formula: kJ = J × 0.001
Reverse: J = kJ × 1,000
Step-by-Step Example
- Start with your value in Joule. For example: 5 J
- Multiply by the conversion factor: 5 x 0.001
- The result is: 0.005 kJ
About Joule
The joule is the SI unit of energy. One joule equals the work done when a force of one newton moves an object one meter.
Common uses: physics, electrical engineering, chemistry.
About Kilojoule
The kilojoule (kJ) is a unit of energy and work. One kilojoule equals 1000 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: energy calculations, engineering and science, education.
Frequently Asked Questions
How many Kilojoule are in 1 Joule?
There are exactly 0.001 Kilojoule in 1 Joule. This means the conversion factor from Joule to Kilojoule is 0.001.
What is the formula to convert Joule to Kilojoule?
The formula to convert Joule to Kilojoule is: kJ = J × 0.001. For example, to convert 10 Joule to Kilojoule, you would multiply 10 by 0.001.
What is a Joule?
The joule is the SI unit of energy. One joule equals the work done when a force of one newton moves an object one meter.
What is a Kilojoule?
The kilojoule (kJ) is a unit of energy and work. One kilojoule equals 1000 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What are the common uses of Joule?
The Joule is commonly used in physics, electrical engineering, chemistry.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Joule to Kilojoule converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/joule-to-kilojoule