Millijoule is 0.001 joule units.
Millijoules to Ergs Converter — mJ to erg
Convert Millijoule (mJ) to Erg (erg) using the exact conversion factor (1 millijoule = 10,000 erg). See the formula, worked examples, and conversion table.
Millijoules to Ergs converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
An erg is a CGS energy unit.
Result = input x 0.001 / 1e-7.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Millijoules to Ergs
Millijoule and Erg both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: Millijoule is 0.001 joule units, and an erg is a CGS energy unit.
Formula
ergs = millijoules × 10000
This factor comes from each unit's defined relationship to the category's base unit: 1 millijoule equals 0.001 base units, and 1 erg equals 1e-7 base units, so dividing one by the other gives the direct millijoule-to-erg factor of 10000.
Simple example
1 mJ × 10000 = 10,000 erg
1 millijoule = 10,000 ergs.
Real-world example
100 mJ × 10000 = 1,000,000 erg
100 millijoules = 1,000,000 ergs.
Conversion table
| Millijoule (mJ) | Erg (erg) |
|---|---|
| 1 mJ | 10,000 erg |
| 10 mJ | 100,000 erg |
| 50 mJ | 500,000 erg |
| 100 mJ | 1,000,000 erg |
| 500 mJ | 5,000,000 erg |
| 1,000 mJ | 10,000,000 erg |
Reverse conversion: Erg to Millijoule
1 erg × 0.0001 = 0.0001 mJ
1 erg = 0.0001 millijoules.
millijoules = ergs × 0.0001
For a page dedicated to this direction, see Erg to Millijoule.
Understanding the Millijoule (mJ)
Millijoule is 0.001 joule units.
Understanding the Erg (erg)
An erg is a CGS energy unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many ergs are in 1 millijoule?
1 millijoule equals 10,000 ergs, using the exact defined conversion factor rather than an estimate.
How do I convert millijoule to erg?
Multiply the millijoule value by 10000. The converter above does this instantly to whatever precision you set.
How do I convert erg back to millijoule?
Use the reverse factor: 1 erg equals 0.0001 millijoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a millijoule?
Millijoule (mJ) is a unit of engineering.
What is a erg?
Erg (erg) is a unit of engineering.
Is the millijoule to erg conversion exact?
Yes. Both millijoule and erg are defined by fixed standards rather than physical artifacts, so the factor of 10000 used above is exact to as many digits as you choose to display.
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.