Millijoule is 0.001 joule units.
Millijoules to Decijoules Converter — mJ to dJ
Convert Millijoule (mJ) to Decijoule (dJ) using the exact conversion factor (1 millijoule = 0.01 decijoule). See the formula, worked examples, and conversion table.
Millijoules to Decijoules converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
Decijoule is 0.1 joule units.
Result = input x 0.001 / 0.1.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Millijoules to Decijoules
Millijoule and Decijoule both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Specifically: Millijoule is 0.001 joule units, and decijoule is 0.1 joule units.
Formula
decijoules = millijoules × 0.01
This factor comes from each unit's defined relationship to the category's base unit: 1 millijoule equals 0.001 base units, and 1 decijoule equals 0.1 base units, so dividing one by the other gives the direct millijoule-to-decijoule factor of 0.01.
Simple example
1 mJ × 0.01 = 0.01 dJ
1 millijoule = 0.01 decijoules.
Real-world example
100 mJ × 0.01 = 1 dJ
100 millijoules = 1 decijoule.
Conversion table
| Millijoule (mJ) | Decijoule (dJ) |
|---|---|
| 1 mJ | 0.01 dJ |
| 10 mJ | 0.1 dJ |
| 100 mJ | 1 dJ |
| 500 mJ | 5 dJ |
| 1,000 mJ | 10 dJ |
| 2,000 mJ | 20 dJ |
Reverse conversion: Decijoule to Millijoule
0.01 dJ × 100 = 1 mJ
0.01 decijoules = 1 millijoule.
millijoules = decijoules × 100
For a page dedicated to this direction, see Decijoule to Millijoule.
Understanding the Millijoule (mJ)
Millijoule is 0.001 joule units.
Understanding the Decijoule (dJ)
Decijoule is 0.1 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many decijoules are in 1 millijoule?
1 millijoule equals 0.01 decijoules, using the exact defined conversion factor rather than an estimate.
How do I convert millijoule to decijoule?
Multiply the millijoule value by 0.01. The converter above does this instantly to whatever precision you set.
How do I convert decijoule back to millijoule?
Use the reverse factor: 1 decijoule equals 100 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 energy.
What is a decijoule?
Decijoule (dJ) is a unit of energy.
Is the millijoule to decijoule conversion exact?
Yes. Both millijoule and decijoule are defined by fixed standards rather than physical artifacts, so the factor of 0.01 used above is exact to as many digits as you choose to display.