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 Megajoules
Convert Calorie (cal) to Megajoule (MJ) instantly with an exact formula, conversion table, and FAQ.
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Convert calories (cal) to megajoules (MJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
MJ = cal × 0.000004184
Results update instantly for Calories to Megajoules conversions.
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Formula
MJ = cal × 0.000004184
cal = MJ × 239005.7361
Conversion table
| 1 cal | 0.000004 MJ |
| 5 cal | 0.000021 MJ |
| 10 cal | 0.000042 MJ |
| 20 cal | 0.000084 MJ |
| 50 cal | 0.000209 MJ |
| 100 cal | 0.000418 MJ |
| 500 cal | 0.002092 MJ |
| 1000 cal | 0.004184 MJ |
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How the formula works
Both calorie and megajoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in calories by 0.000004184 to get megajoules. To reverse the conversion, multiply a megajoule value by 239005.7361 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 Megajoule (MJ)?
A megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
How do I convert calories to megajoules?
Multiply the calorie value by 0.000004184 to get the equivalent in megajoules. For example, 5 cal × 0.000004184 = 0.000021 MJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 0.000004184 is an exact, non-rounded value.
Can I convert megajoules back to calories?
Yes. Divide the megajoule value by 0.000004184, or multiply it by 239005.7361, to get calories.
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About converting calories to megajoules
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 megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
Use this calculator to move between calories and megajoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.