A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
Rontojoules to Kilocalories
Convert Rontojoule (rJ) to Kilocalorie (kcal) instantly with an exact formula, conversion table, and FAQ.
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Convert rontojoules (rJ) to kilocalories (kcal) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels.
kcal = rJ × 2.390057361e-31
Results update instantly for Rontojoules to Kilocalories conversions.
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Formula
kcal = rJ × 2.390057361e-31
rJ = kcal × 4.184000000e+30
Conversion table
| 1 rJ | 2.390057e-31 kcal |
| 5 rJ | 1.195029e-30 kcal |
| 10 rJ | 2.390057e-30 kcal |
| 20 rJ | 4.780115e-30 kcal |
| 50 rJ | 1.195029e-29 kcal |
| 100 rJ | 2.390057e-29 kcal |
| 500 rJ | 1.195029e-28 kcal |
| 1000 rJ | 2.390057e-28 kcal |
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How the formula works
Both rontojoule and kilocalorie measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in rontojoules by 2.390057361e-31 to get kilocalories. To reverse the conversion, multiply a kilocalorie value by 4.184000000e+30 to get back to rontojoules.
Frequently asked questions
What is Rontojoule (rJ)?
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
What is Kilocalorie (kcal)?
A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels.
How do I convert rontojoules to kilocalories?
Multiply the rontojoule value by 2.390057361e-31 to get the equivalent in kilocalories. For example, 5 rJ × 2.390057361e-31 = 1.195029e-30 kcal.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 2.390057361e-31 is an exact, non-rounded value.
Can I convert kilocalories back to rontojoules?
Yes. Divide the kilocalorie value by 2.390057361e-31, or multiply it by 4.184000000e+30, to get rontojoules.
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About converting rontojoules to kilocalories
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix. A kilocalorie (kcal) equals 1,000 small calories and is the unit behind the food "Calorie" shown on nutrition labels.
Use this calculator to move between rontojoules and kilocalories accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.