A petajoule (PJ) is a metric-prefixed unit of energy equal to 1015 joules, using the SI peta prefix.
Petajoules to Millijoules
Convert Petajoule (PJ) to Millijoule (mJ) instantly with an exact formula, conversion table, and FAQ.
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Convert petajoules (PJ) to millijoules (mJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
mJ = PJ × 1.000000000e+18
Results update instantly for Petajoules to Millijoules conversions.
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Formula
mJ = PJ × 1.000000000e+18
PJ = mJ × 1.000000000e-18
Conversion table
| 1 PJ | 1.000000e+18 mJ |
| 5 PJ | 5.000000e+18 mJ |
| 10 PJ | 1.000000e+19 mJ |
| 20 PJ | 2.000000e+19 mJ |
| 50 PJ | 5.000000e+19 mJ |
| 100 PJ | 1.000000e+20 mJ |
| 500 PJ | 5.000000e+20 mJ |
| 1000 PJ | 1.000000e+21 mJ |
Related conversions
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How the formula works
Both petajoule and millijoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in petajoules by 1.000000000e+18 to get millijoules. To reverse the conversion, multiply a millijoule value by 1.000000000e-18 to get back to petajoules.
Frequently asked questions
What is Petajoule (PJ)?
A petajoule (PJ) is a metric-prefixed unit of energy equal to 1015 joules, using the SI peta prefix.
What is Millijoule (mJ)?
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
How do I convert petajoules to millijoules?
Multiply the petajoule value by 1.000000000e+18 to get the equivalent in millijoules. For example, 5 PJ × 1.000000000e+18 = 5.000000e+18 mJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e+18 is an exact, non-rounded value.
Can I convert millijoules back to petajoules?
Yes. Divide the millijoule value by 1.000000000e+18, or multiply it by 1.000000000e-18, to get petajoules.
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About converting petajoules to millijoules
A petajoule (PJ) is a metric-prefixed unit of energy equal to 1015 joules, using the SI peta prefix. A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
Use this calculator to move between petajoules and millijoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.