A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix.
Gigajoules to Calories
Convert Gigajoule (GJ) to Calorie (cal) instantly with an exact formula, conversion table, and FAQ.
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Convert gigajoules (GJ) to calories (cal) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
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.
cal = GJ × 239005736.1
Results update instantly for Gigajoules to Calories conversions.
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Formula
cal = GJ × 239005736.1
GJ = cal × 4.184000000e-09
Conversion table
| 1 GJ | 2.390057e+08 cal |
| 5 GJ | 1.195029e+09 cal |
| 10 GJ | 2.390057e+09 cal |
| 20 GJ | 4.780115e+09 cal |
| 50 GJ | 1.195029e+10 cal |
| 100 GJ | 2.390057e+10 cal |
| 500 GJ | 1.195029e+11 cal |
| 1000 GJ | 2.390057e+11 cal |
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How the formula works
Both gigajoule and calorie measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in gigajoules by 239005736.1 to get calories. To reverse the conversion, multiply a calorie value by 4.184000000e-09 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 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.
How do I convert gigajoules to calories?
Multiply the gigajoule value by 239005736.1 to get the equivalent in calories. For example, 5 GJ × 239005736.1 = 1.195029e+09 cal.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 239005736.1 is an exact, non-rounded value.
Can I convert calories back to gigajoules?
Yes. Divide the calorie value by 239005736.1, or multiply it by 4.184000000e-09, to get gigajoules.
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About converting gigajoules to calories
A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix. 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.
Use this calculator to move between gigajoules and calories accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.