A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix.
Gigajoules to Kilocalories
Convert Gigajoule (GJ) to Kilocalorie (kcal) instantly with an exact formula, conversion table, and FAQ.
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Convert gigajoules (GJ) 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 = GJ × 239005.7361
Results update instantly for Gigajoules to Kilocalories conversions.
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Formula
kcal = GJ × 239005.7361
GJ = kcal × 0.000004184
Conversion table
| 1 GJ | 239005.736138 kcal |
| 5 GJ | 1.195029e+06 kcal |
| 10 GJ | 2.390057e+06 kcal |
| 20 GJ | 4.780115e+06 kcal |
| 50 GJ | 1.195029e+07 kcal |
| 100 GJ | 2.390057e+07 kcal |
| 500 GJ | 1.195029e+08 kcal |
| 1000 GJ | 2.390057e+08 kcal |
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How the formula works
Both gigajoule and kilocalorie measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in gigajoules by 239005.7361 to get kilocalories. To reverse the conversion, multiply a kilocalorie value by 0.000004184 to get back to gigajoules.
Frequently asked questions
What is Gigajoule (GJ)?
A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga 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 gigajoules to kilocalories?
Multiply the gigajoule value by 239005.7361 to get the equivalent in kilocalories. For example, 5 GJ × 239005.7361 = 1.195029e+06 kcal.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 239005.7361 is an exact, non-rounded value.
Can I convert kilocalories back to gigajoules?
Yes. Divide the kilocalorie value by 239005.7361, or multiply it by 0.000004184, to get gigajoules.
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About converting gigajoules to kilocalories
A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga 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 gigajoules 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.