Microjoule is 0.000001 joule units.
Microjoules to Kilojoules Converter — uJ to kJ
Convert Microjoule (uJ) to Kilojoule (kJ) using the exact conversion factor (1 microjoule = 1e-9 kilojoule). See the formula, worked examples, and conversion table.
Microjoules to Kilojoules 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.
Kilojoule is 1000 joule units.
Result = input x 1e-6 / 1000.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Microjoules to Kilojoules
Microjoule and Kilojoule 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: Microjoule is 0.000001 joule units, and kilojoule is 1000 joule units.
Formula
kilojoules = microjoules × 1e-9
This factor comes from each unit's defined relationship to the category's base unit: 1 microjoule equals 0.000001 base units, and 1 kilojoule equals 1000 base units, so dividing one by the other gives the direct microjoule-to-kilojoule factor of 1e-9.
Simple example
1 uJ × 1e-9 = 1e-9 kJ
1 microjoule = 1e-9 kilojoules.
Real-world example
100 uJ × 1e-9 = 1e-7 kJ
100 microjoules = 1e-7 kilojoules.
Conversion table
| Microjoule (uJ) | Kilojoule (kJ) |
|---|---|
| 1 uJ | 1e-9 kJ |
| 10 uJ | 1e-8 kJ |
| 50 uJ | 5e-8 kJ |
| 100 uJ | 1e-7 kJ |
| 500 uJ | 5e-7 kJ |
| 1,000 uJ | 0.000001 kJ |
Reverse conversion: Kilojoule to Microjoule
1e-9 kJ × 1000000000 = 1 uJ
1e-9 kilojoules = 1 microjoules.
microjoules = kilojoules × 1000000000
For a page dedicated to this direction, see Kilojoule to Microjoule.
Understanding the Microjoule (uJ)
Microjoule is 0.000001 joule units.
Understanding the Kilojoule (kJ)
Kilojoule is 1000 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilojoules are in 1 microjoule?
1 microjoule equals 1e-9 kilojoules, using the exact defined conversion factor rather than an estimate.
How do I convert microjoule to kilojoule?
Multiply the microjoule value by 1e-9. The converter above does this instantly to whatever precision you set.
How do I convert kilojoule back to microjoule?
Use the reverse factor: 1 kilojoule equals 1,000,000,000 microjoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a microjoule?
Microjoule (uJ) is a unit of engineering.
What is a kilojoule?
Kilojoule (kJ) is a unit of engineering.
Is the microjoule to kilojoule conversion exact?
Yes. Both microjoule and kilojoule are defined by fixed standards rather than physical artifacts, so the factor of 1e-9 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.