A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels.
Kilocalories to Microjoules
Convert Kilocalorie (kcal) to Microjoule (uJ) instantly with an exact formula, conversion table, and FAQ.
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Convert kilocalories (kcal) 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 = kcal × 4184000000
Results update instantly for Kilocalories to Microjoules conversions.
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Formula
uJ = kcal × 4184000000
kcal = uJ × 2.390057361e-10
Conversion table
| 1 kcal | 4.184000e+09 uJ |
| 5 kcal | 2.092000e+10 uJ |
| 10 kcal | 4.184000e+10 uJ |
| 20 kcal | 8.368000e+10 uJ |
| 50 kcal | 2.092000e+11 uJ |
| 100 kcal | 4.184000e+11 uJ |
| 500 kcal | 2.092000e+12 uJ |
| 1000 kcal | 4.184000e+12 uJ |
Related conversions
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How the formula works
Both kilocalorie and microjoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in kilocalories by 4184000000 to get microjoules. To reverse the conversion, multiply a microjoule value by 2.390057361e-10 to get back to kilocalories.
Frequently asked questions
What is Kilocalorie (kcal)?
A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels.
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 kilocalories to microjoules?
Multiply the kilocalorie value by 4184000000 to get the equivalent in microjoules. For example, 5 kcal × 4184000000 = 2.092000e+10 uJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 4184000000 is an exact, non-rounded value.
Can I convert microjoules back to kilocalories?
Yes. Divide the microjoule value by 4184000000, or multiply it by 2.390057361e-10, to get kilocalories.
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About converting kilocalories to microjoules
A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels. 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 kilocalories 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.