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 Microjoules
Convert Calorie (cal) to Microjoule (uJ) instantly with an exact formula, conversion table, and FAQ.
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Convert calories (cal) to microjoules (uJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro prefix.
uJ = cal × 4184000
Results update instantly for Calories to Microjoules conversions.
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Formula
uJ = cal × 4184000
cal = uJ × 2.390057361e-07
Conversion table
| 1 cal | 4.184000e+06 uJ |
| 5 cal | 2.092000e+07 uJ |
| 10 cal | 4.184000e+07 uJ |
| 20 cal | 8.368000e+07 uJ |
| 50 cal | 2.092000e+08 uJ |
| 100 cal | 4.184000e+08 uJ |
| 500 cal | 2.092000e+09 uJ |
| 1000 cal | 4.184000e+09 uJ |
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How the formula works
Both calorie and microjoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in calories by 4184000 to get microjoules. To reverse the conversion, multiply a microjoule value by 2.390057361e-07 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 Microjoule (uJ)?
A microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro prefix.
How do I convert calories to microjoules?
Multiply the calorie value by 4184000 to get the equivalent in microjoules. For example, 5 cal × 4184000 = 2.092000e+07 uJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 4184000 is an exact, non-rounded value.
Can I convert microjoules back to calories?
Yes. Divide the microjoule value by 4184000, or multiply it by 2.390057361e-07, to get calories.
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About converting calories to microjoules
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 microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro prefix.
Use this calculator to move between calories and microjoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.