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The conversion between calories and kilojoules is a fundamental calculation in energy measurement. One calorie (cal) is equivalent to 4.184 joules, and one kilojoule (kJ) equals 1000 joules.
The calculator uses the simple conversion formula:
Where:
Explanation: This conversion factor is based on the definition of the thermochemical calorie, which is the amount of energy needed to raise the temperature of 1 gram of water by 1°C at standard conditions.
Details: Understanding energy conversions is essential in nutrition science, physics, chemistry, and engineering. Many countries use kilojoules on food labels while others use calories, making conversion necessary for accurate comparisons.
Tips: Simply enter the number of calories you want to convert. The calculator will instantly provide the equivalent energy in kilojoules.
Q1: What's the difference between calories and kilojoules?
A: Both measure energy, but kilojoules are part of the metric system (SI units) while calories are not. 1 kilojoule equals approximately 0.239 calories.
Q2: Are food calories the same as physics calories?
A: Food calories (Calories with capital C) are actually kilocalories (1000 physics calories). This calculator uses physics calories.
Q3: Why is the conversion factor 4.184?
A: This value was determined experimentally as the amount of work needed to raise the temperature of water under specific conditions.
Q4: How accurate is this conversion?
A: The 4.184 factor is precise for thermochemical calories. Other calorie definitions (IT, 15°C) have slightly different conversion factors.
Q5: When would I need to convert between these units?
A: Common uses include interpreting international food labels, scientific research, dietary planning, and exercise physiology.