Convert Calories to Kilojoules
Instantly convert Calories (cal) to Kilojoules (kJ) with our free online calculator.
Formula: cal to kJ — multiply by 0.004184
Reference Table
| Calories (cal) | Kilojoules (kJ) |
|---|---|
| 1 | 0.004184 |
| 5 | 0.02092 |
| 10 | 0.04184 |
| 25 | 0.1046 |
| 50 | 0.2092 |
| 100 | 0.4184 |
How to Convert Calories to Kilojoules
Formula
To convert Calories (cal) to Kilojoules (kJ): multiply by 0.004184
Step-by-Step
- Start with your value in Calories (cal).
- Multiply by 0.004184 to perform the conversion.
- The result is your value expressed in Kilojoules (kJ).
Conversion Factor
1 cal = 0.004184 kJ
Reverse Factor
1 kJ = 239.006 cal
Worked Example
Convert 25 Calories to Kilojoules: 25 cal = 0.1046 kJ
About Calorie (cal)
The "small" gram-calorie, equal to the energy needed to raise one gram of water by 1°C (exactly 4.184 joules). This is the scientific calorie used in chemistry and physics literature — not the larger Calorie (Cal, capital C) used on US food labels, which is actually a kilocalorie (1 kcal = 1,000 gram-calories). This ambiguity between "cal" and "Cal" is a notorious source of confusion when comparing nutrition data to scientific sources.
About Kilojoule (kJ)
A metric unit of energy equal to 1,000 joules. Kilojoules are the standard unit for food energy outside the United States — Australia, New Zealand, and the European Union all display kJ on nutrition panels. A Big Mac is roughly 2,220 kJ; an adult daily energy intake is typically 8,000–10,500 kJ. The kJ is also the natural engineering unit for mechanical work, battery capacity, and small-scale thermodynamic calculations.
Quick Facts
- 1 Calorie equals 0.004184 Kilojoules
- 1 Kilojoule equals 239.006 Calories
- Calorie is a unit of energy
- Kilojoule is a unit of energy
- This conversion is commonly used in nutrition, electrical billing, physics, and mechanical engineering
- The Kilojoule belongs to the metric system
Common Calorie to Kilojoule Conversions
| Calories (cal) | Kilojoules (kJ) |
|---|---|
| 0.01 | 0.00004184 |
| 0.1 | 0.0004184 |
| 0.25 | 0.001046 |
| 0.5 | 0.002092 |
| 1 | 0.004184 |
| 2 | 0.008368 |
| 3 | 0.012552 |
| 5 | 0.02092 |
| 10 | 0.04184 |
| 15 | 0.06276 |
| 20 | 0.08368 |
| 25 | 0.1046 |
| 50 | 0.2092 |
| 75 | 0.3138 |
| 100 | 0.4184 |
| 250 | 1.046 |
| 500 | 2.092 |
| 1000 | 4.184 |
| 5000 | 20.92 |
| 10000 | 41.84 |
Understanding Calories
The Calorie (symbol: cal) is a unit of energy. The "small" gram-calorie, equal to the energy needed to raise one gram of water by 1°C (exactly 4.184 joules). This is the scientific calorie used in chemistry and physics literature — not the larger Calorie (Cal, capital C) used on US food labels, which is actually a kilocalorie (1 kcal = 1,000 gram-calories). This ambiguity between "cal" and "Cal" is a notorious source of confusion when comparing nutrition data to scientific sources.
Calories are commonly used in nutrition, electrical billing, physics, and mechanical engineering.
Understanding Kilojoules
The Kilojoule (symbol: kJ) is a unit of energy. A metric unit of energy equal to 1,000 joules. Kilojoules are the standard unit for food energy outside the United States — Australia, New Zealand, and the European Union all display kJ on nutrition panels. A Big Mac is roughly 2,220 kJ; an adult daily energy intake is typically 8,000–10,500 kJ. The kJ is also the natural engineering unit for mechanical work, battery capacity, and small-scale thermodynamic calculations.
It belongs to the metric measurement system.
Kilojoules are commonly used in nutrition, electrical billing, physics, and mechanical engineering.
Why Convert Calories to Kilojoules?
Converting energy between Calories and Kilojoules is common in physics, nutrition, and engineering. Electricity bills use kilowatt-hours, food labels list calories or kilojoules, and mechanical engineers work with joules and BTUs. Reliable conversion helps professionals and consumers compare energy values across different contexts.
Frequently Asked Questions
How do I convert Calories to Kilojoules?
The "small" gram-calorie, equal to the energy needed to raise one gram of water by 1°C (exactly 4. To convert Calories to Kilojoules, multiply by 0.004184. For example, 25 cal equals 0.1046 kJ.
How many Kilojoules are in 1 Calorie?
There are 0.004184 Kilojoules in 1 Calorie.
How many Calories are in 1 Kilojoule?
There are 239.006 Calories in 1 Kilojoule.
What is the formula for Calorie to Kilojoule conversion?
The formula is: multiply by 0.004184. This means 1 cal = 0.004184 kJ.
Is a Calorie bigger than a Kilojoule?
Yes. One Calorie is larger than one Kilojoule because 1 cal equals 0.004184 kJ, which is less than 1.
When do you need to convert between Calories and Kilojoules?
A metric unit of energy equal to 1,000 joules. Calorie and Kilojoule are both energy units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.