A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
Calories to Millijoules
Convert Calorie (cal) to Millijoule (mJ) instantly with an exact formula, conversion table, and FAQ.
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Convert calories (cal) 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 = cal × 4184
Results update instantly for Calories to Millijoules conversions.
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Formula
mJ = cal × 4184
cal = mJ × 0.0002390057361
Conversion table
| 1 cal | 4184 mJ |
| 5 cal | 20920 mJ |
| 10 cal | 41840 mJ |
| 20 cal | 83680 mJ |
| 50 cal | 209200 mJ |
| 100 cal | 418400 mJ |
| 500 cal | 2.092000e+06 mJ |
| 1000 cal | 4.184000e+06 mJ |
Related conversions
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How the formula works
Both calorie and millijoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in calories by 4184 to get millijoules. To reverse the conversion, multiply a millijoule value by 0.0002390057361 to get back to calories.
Frequently asked questions
What is Calorie (cal)?
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
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 calories to millijoules?
Multiply the calorie value by 4184 to get the equivalent in millijoules. For example, 5 cal × 4184 = 20920 mJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 4184 is an exact, non-rounded value.
Can I convert millijoules back to calories?
Yes. Divide the millijoule value by 4184, or multiply it by 0.0002390057361, to get calories.
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About converting calories to millijoules
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C. 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 calories 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.