Millijoule to Joule Converter
Convert Millijoule (mJ) to Joule (J) instantly. 1 mJ = 0.001 J.
Energy Converter
27 units available
1 mJ = 0.001 J
Formula:
J = mJ × 0.001With your value: 1 mJ = 0.001 J
How big is that?
Everyday references on a logarithmic scale, all expressed in millijoule so you can sanity-check the result.
Other Millijoule to Joule conversions
Millijoule to Joule Conversion Table
| Millijoule (mJ) | Joule (J) |
|---|---|
| 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 |
Joule to Millijoule Conversion Table
| Joule (J) | Millijoule (mJ) |
|---|---|
| 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.
Millijoule (mJ)
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
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
How to Convert Millijoule to Joule
To convert from Millijoule (mJ) to Joule (J), multiply the value by 0.001.
Formula: J = mJ × 0.001
Reverse: mJ = J × 1,000
Step-by-Step Example
- Start with your value in Millijoule. For example: 5 mJ
- Multiply by the conversion factor: 5 x 0.001
- The result is: 0.005 J
About Millijoule
The millijoule (mJ) is a unit of energy and work. One millijoule equals 0.001 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.
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.
Frequently Asked Questions
How many Joule are in 1 Millijoule?
There are exactly 0.001 Joule in 1 Millijoule. This means the conversion factor from Millijoule to Joule is 0.001.
What is the formula to convert Millijoule to Joule?
The formula to convert Millijoule to Joule is: J = mJ × 0.001. For example, to convert 10 Millijoule to Joule, you would multiply 10 by 0.001.
What is a Millijoule?
The millijoule (mJ) is a unit of energy and work. One millijoule equals 0.001 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 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 are the common uses of Millijoule?
The Millijoule is commonly used in energy calculations, engineering and science, education.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Millijoule to Joule converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/millijoule-to-joule