Millijoules to Joules converter
Convert Millijoules (mJ) to Joules (J). Calculate a value, check the formula and compare common measurements.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Value | Enter value using the definition in the method and example. |
| From | Select the unit or currency in which the entered number is currently expressed. |
| To | Select the unit or currency you need for the answer. |
Understanding your result
The converted value describes the same energy quantity in the selected target unit. Display rounding does not add precision to the original measurement.
Common mistakes
- Confusing the source and target units, or overlooking a prefix or case-sensitive symbol.
Check your calculation
- Convert to the target unit and then reverse the direction. Within display rounding, you should recover the original value.
Read the energy measurement guide · Calculation checks, sources and review limits
How do I convert millijoules to joules?
Enter the value in millijoules to find the same energy quantity in joules. The number changes to match the unit; the underlying quantity stays the same. Check the definitions below when a unit has more than one convention.
Common uses
- Compare energy amounts stated in different units.
- Translate energy measurements on a specification or meter.
How it works
For the displayed direction, 1 mJ equals 0.001 J. The engine converts through the shared energy base quantity. Calories are thermochemical. BTU uses the international-table definition. Foot-pounds mean foot-pounds force. The multiplier is derived from the two centralized unit factors. Keep full precision until the final result; displayed answers use up to 12 significant digits. SI prefixes specify powers of ten: femto 10^-15, pico 10^-12, nano 10^-9, micro 10^-6, milli 10^-3, kilo 10^3, mega 10^6, giga 10^9 and tera 10^12. Unit symbols are case-sensitive. The numerical conversion uses the ratio of the source and target scale factors.
Worked example
10 mJ converts to 0.01 J. For the reverse direction, swap the units and enter 0.01 J; the result is approximately 10 mJ.
FAQ
How do I convert mJ to J?
J = mJ × 0.001
Which definition is used?
Calories are thermochemical. BTU uses the international-table definition. Foot-pounds mean foot-pounds force.
Common values
Use “Swap units” above for the reverse conversion. Values below are rounded to six significant digits.
| Millijoules | Joules |
|---|---|
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 20 | 0.02 |
| 30 | 0.03 |
| 50 | 0.05 |
| 100 | 0.1 |