Millijoule is 0.001 joule units.
Millijoules to Microjoules Converter — mJ to uJ
Convert Millijoule (mJ) to Microjoule (uJ) using the exact conversion factor (1 millijoule = 1,000 microjoule). See the formula, worked examples, and conversion table.
Millijoules to Microjoules 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.
Microjoule is 0.000001 joule units.
Result = input x 0.001 / 1e-6.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Millijoules to Microjoules
Millijoule and Microjoule 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 microjoule is 0.000001 joule units.
Formula
microjoules = millijoules × 1000
This factor comes from each unit's defined relationship to the category's base unit: 1 millijoule equals 0.001 base units, and 1 microjoule equals 0.000001 base units, so dividing one by the other gives the direct millijoule-to-microjoule factor of 1000.
Simple example
1 mJ × 1000 = 1,000 uJ
1 millijoule = 1,000 microjoules.
Real-world example
100 mJ × 1000 = 100,000 uJ
100 millijoules = 100,000 microjoules.
Conversion table
| Millijoule (mJ) | Microjoule (uJ) |
|---|---|
| 1 mJ | 1,000 uJ |
| 10 mJ | 10,000 uJ |
| 100 mJ | 100,000 uJ |
| 500 mJ | 500,000 uJ |
| 1,000 mJ | 1,000,000 uJ |
| 2,000 mJ | 2,000,000 uJ |
Reverse conversion: Microjoule to Millijoule
1 uJ × 0.001 = 0.001 mJ
1 microjoule = 0.001 millijoules.
millijoules = microjoules × 0.001
For a page dedicated to this direction, see Microjoule to Millijoule.
Understanding the Millijoule (mJ)
Millijoule is 0.001 joule units.
Understanding the Microjoule (uJ)
Microjoule is 0.000001 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many microjoules are in 1 millijoule?
1 millijoule equals 1,000 microjoules, using the exact defined conversion factor rather than an estimate.
How do I convert millijoule to microjoule?
Multiply the millijoule value by 1000. The converter above does this instantly to whatever precision you set.
How do I convert microjoule back to millijoule?
Use the reverse factor: 1 microjoule equals 0.001 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 microjoule?
Microjoule (uJ) is a unit of energy.
Is the millijoule to microjoule conversion exact?
Yes. Both millijoule and microjoule are defined by fixed standards rather than physical artifacts, so the factor of 1000 used above is exact to as many digits as you choose to display.