Millijoules to Kilojoules Converter
Enter the energy in millijoules below to convert it to kilojoules.
Convert Millijoules to Kilojoules
Enter a value in millijoules (mJ) to convert to kilojoules (kJ).
Millijoule to Kilojoule Conversion Table
Table showing various millijoule measurements converted to kilojoules. Click any preset value or arrow to load it into the converter.
| Millijoules (mJ) | Kilojoules (kJ) |
|---|---|
| 1 mJ | 0.000001 kJ |
| 10 mJ | 0.00001 kJ |
| 100 mJ | 0.0001 kJ |
| 1,000 mJ | 0.001 kJ |
| 10,000 mJ | 0.01 kJ |
| 100,000 mJ | 0.1 kJ |
| 1,000,000 mJ | 1 kJ |
| 5,000,000 mJ | 5 kJ |
| 10,000,000 mJ | 10 kJ |
| 25,400,000 mJ | 25.4 kJ |
How to Convert Millijoules to Kilojoules
To convert millijoules to kilojoules, multiply the energy by the following conversion ratio: 0.000001 kilojoules/millijoule.
Since one millijoule is equal to 0.000001 kilojoules, you can use this simple formula to convert:
The energy in kilojoules is equal to the energy in millijoules multiplied by 0.000001.
For example, here's how to convert 5 millijoules to kilojoules using the formula above.
How Many Kilojoules Are in a Millijoule?
There are 0.000001 kilojoules in a millijoule, which is why we use this value in the formula above.
Our millijoule to kilojoule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Millijoules and kilojoules are both units used to measure energy. Keep reading to learn more about each unit.
What Is a Millijoule?
A millijoule is a unit of energy equal to 1/1,000 of a joule (0.001 J). One-thousandth of a Joule. [1]
The millijoule is classified as a metric and SI-compatible unit of energy. Millijoules can be abbreviated as mJ; for example, 1 millijoule can be written as 1 mJ.
In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millijoule (mJ) a convenient decimal multiple of the joule (J).
In practice, millijoules (mJ) are widely used across fine-tolerance laboratory, analytical, and micro-scale energy measurements within SI metric workflows, engineering documentation, and technical data sheets.
What Is a Kilojoule?
A kilojoule is a unit of energy equal to 1,000 joules (J), the base unit for energy. Equal to 1,000 Joules. [2]
The kilojoule is classified as a metric and SI-compatible unit of energy. Kilojoules can be abbreviated as kJ; for example, 1 kilojoule can be written as 1 kJ.
In the metric system, "kilo" is the standard SI prefix for thousands, or 10³. This makes the kilojoule (kJ) a convenient decimal multiple of the joule (J).
In practice, kilojoules (kJ) are widely used across large-scale industrial, bulk, and macro-level energy specifications within SI metric workflows, engineering documentation, and technical data sheets.
When converting energy between millijoules (mJ) and kilojoules (kJ), keep full floating-point precision (1 mJ = 0.000001 kJ; 1 kJ = 1,000,000 mJ) during intermediate calculations and round only the final kilojoule figure to match your instrument tolerance.
More Millijoule & Kilojoule Conversions
Need to calculate in the opposite direction? Use our kilojoules to millijoules calculator to switch your starting unit immediately. You can also explore related tools such as converting kilojoules to millijoules, converting joules to kilojoules, or converting kilocalories to kilojoules.
Convert from Millijoules
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Millijoules (mJ) to Kilojoules (kJ)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Millijoule (mJ) & Kilojoule (kJ)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (mJ to kJ)