Decijoule is 0.1 joule units.
Decijoules to Millijoules Converter — dJ to mJ
Convert Decijoule (dJ) to Millijoule (mJ) using the exact conversion factor (1 decijoule = 100 millijoule). See the formula, worked examples, and conversion table.
Decijoules to Millijoules 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.
Millijoule is 0.001 joule units.
Result = input x 0.1 / 0.001.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Decijoules to Millijoules
Decijoule and Millijoule 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: Decijoule is 0.1 joule units, and millijoule is 0.001 joule units.
Formula
millijoules = decijoules × 100
This factor comes from each unit's defined relationship to the category's base unit: 1 decijoule equals 0.1 base units, and 1 millijoule equals 0.001 base units, so dividing one by the other gives the direct decijoule-to-millijoule factor of 100.
Simple example
1 dJ × 100 = 100 mJ
1 decijoule = 100 millijoules.
Real-world example
100 dJ × 100 = 10,000 mJ
100 decijoules = 10,000 millijoules.
Conversion table
| Decijoule (dJ) | Millijoule (mJ) |
|---|---|
| 1 dJ | 100 mJ |
| 10 dJ | 1,000 mJ |
| 50 dJ | 5,000 mJ |
| 100 dJ | 10,000 mJ |
| 500 dJ | 50,000 mJ |
| 1,000 dJ | 100,000 mJ |
Reverse conversion: Millijoule to Decijoule
100 mJ × 0.01 = 1 dJ
100 millijoules = 1 decijoule.
decijoules = millijoules × 0.01
For a page dedicated to this direction, see Millijoule to Decijoule.
Understanding the Decijoule (dJ)
Decijoule is 0.1 joule units.
Understanding the Millijoule (mJ)
Millijoule is 0.001 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millijoules are in 1 decijoule?
1 decijoule equals 100 millijoules, using the exact defined conversion factor rather than an estimate.
How do I convert decijoule to millijoule?
Multiply the decijoule value by 100. The converter above does this instantly to whatever precision you set.
How do I convert millijoule back to decijoule?
Use the reverse factor: 1 millijoule equals 0.01 decijoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a decijoule?
Decijoule (dJ) is a unit of engineering.
What is a millijoule?
Millijoule (mJ) is a unit of engineering.
Is the decijoule to millijoule conversion exact?
Yes. Both decijoule and millijoule are defined by fixed standards rather than physical artifacts, so the factor of 100 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.