Convert Kilojoules to Calories
Instantly convert Kilojoules (kJ) to Calories (cal) with our free online calculator.
Formula: kJ to cal — multiply by 239.006
Reference Table
| Kilojoules (kJ) | Calories (cal) |
|---|---|
| 1 | 239.006 |
| 5 | 1195.03 |
| 10 | 2390.06 |
| 25 | 5975.14 |
| 50 | 11950.3 |
| 100 | 23900.6 |
How to Convert Kilojoules to Calories
Formula
To convert Kilojoules (kJ) to Calories (cal): multiply by 239.006
Step-by-Step
- Start with your value in Kilojoules (kJ).
- Multiply by 239.006 to perform the conversion.
- The result is your value expressed in Calories (cal).
Conversion Factor
1 kJ = 239.006 cal
Reverse Factor
1 cal = 0.004184 kJ
Worked Example
Convert 25 Kilojoules to Calories: 25 kJ = 5975.14 cal
About Kilojoule (kJ)
A metric unit of energy equal to exactly 1,000 joules. Kilojoules are the working unit for food-energy labelling outside the United States — Australia and New Zealand display kJ-only nutrition panels per FSANZ standards 1.2.7 / 1.2.8, the European Union requires kJ alongside kcal per EU Regulation 1169/2011, and Codex Alimentarius (the international food labelling standard) uses kJ. Reference values: a Big Mac is ~2,220 kJ, an adult daily energy intake is 8,000-10,500 kJ (about 2,000-2,500 kcal) per WHO/FAO Recommended Dietary Allowances, a 350 mL soft drink ~600 kJ. The kJ is also the natural engineering unit for small-scale mechanical work (joules per stroke on a punch press), small-cell battery capacity (e.g., a smartphone Li-ion at ~40 kJ), and small-scale thermodynamic calculations like an espresso machine's per-shot energy budget (~20 kJ). 1 kJ = 0.2389 kcal = 0.948 BTU = 277.8 mWh.
About Calorie (cal)
The 'small' gram-calorie (also called thermochemical calorie), defined as exactly 4.184 joules per ISO 31-4 / IUPAC convention — the energy needed to raise one gram of liquid water by 1 °C at standard conditions. This is the scientific calorie used throughout chemistry, physics, and biochemistry literature: enzyme kinetic data, calorimetric measurements (DSC instruments report energy in cal/g for melting transitions), Hess's law calculations, and the thermochemistry tables in the CRC Handbook all use cal. The gram-calorie is NOT the larger 'Calorie' (Cal, capital C) used on US food labels, which is actually a kilocalorie (1 Cal = 1 kcal = 1,000 gram-calories). The cal/Cal naming clash is a notorious source of confusion when cross-referencing nutrition data against scientific literature — a 'low-calorie' food labelled 'only 100 Calories' delivers 100,000 small calories. Two slightly-different historical 'calorie' definitions exist (thermochemical 4.184 J; 'International Table' or IT calorie 4.1868 J), with the thermochemical version dominant in modern usage.
Quick Facts
- 1 Kilojoule equals 239.006 Calories
- 1 Calorie equals 0.004184 Kilojoules
- Kilojoule is a unit of energy
- Calorie 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 Kilojoule to Calorie Conversions
| Kilojoules (kJ) | Calories (cal) |
|---|---|
| 0.01 | 2.39006 |
| 0.1 | 23.9006 |
| 0.25 | 59.7514 |
| 0.5 | 119.503 |
| 1 | 239.006 |
| 2 | 478.011 |
| 3 | 717.017 |
| 5 | 1195.03 |
| 10 | 2390.06 |
| 15 | 3585.09 |
| 20 | 4780.11 |
| 25 | 5975.14 |
| 50 | 11950.3 |
| 75 | 17925.4 |
| 100 | 23900.6 |
| 250 | 59751.4 |
| 500 | 119503 |
| 1000 | 239006 |
| 5000 | 1195030 |
| 10000 | 2390060 |
Understanding Kilojoules
The Kilojoule (symbol: kJ) is a unit of energy. A metric unit of energy equal to exactly 1,000 joules. Kilojoules are the working unit for food-energy labelling outside the United States — Australia and New Zealand display kJ-only nutrition panels per FSANZ standards 1.2.7 / 1.2.8, the European Union requires kJ alongside kcal per EU Regulation 1169/2011, and Codex Alimentarius (the international food labelling standard) uses kJ. Reference values: a Big Mac is ~2,220 kJ, an adult daily energy intake is 8,000-10,500 kJ (about 2,000-2,500 kcal) per WHO/FAO Recommended Dietary Allowances, a 350 mL soft drink ~600 kJ. The kJ is also the natural engineering unit for small-scale mechanical work (joules per stroke on a punch press), small-cell battery capacity (e.g., a smartphone Li-ion at ~40 kJ), and small-scale thermodynamic calculations like an espresso machine's per-shot energy budget (~20 kJ). 1 kJ = 0.2389 kcal = 0.948 BTU = 277.8 mWh.
It belongs to the metric measurement system.
Kilojoules are commonly used in nutrition, electrical billing, physics, and mechanical engineering.
Understanding Calories
The Calorie (symbol: cal) is a unit of energy. The 'small' gram-calorie (also called thermochemical calorie), defined as exactly 4.184 joules per ISO 31-4 / IUPAC convention — the energy needed to raise one gram of liquid water by 1 °C at standard conditions. This is the scientific calorie used throughout chemistry, physics, and biochemistry literature: enzyme kinetic data, calorimetric measurements (DSC instruments report energy in cal/g for melting transitions), Hess's law calculations, and the thermochemistry tables in the CRC Handbook all use cal. The gram-calorie is NOT the larger 'Calorie' (Cal, capital C) used on US food labels, which is actually a kilocalorie (1 Cal = 1 kcal = 1,000 gram-calories). The cal/Cal naming clash is a notorious source of confusion when cross-referencing nutrition data against scientific literature — a 'low-calorie' food labelled 'only 100 Calories' delivers 100,000 small calories. Two slightly-different historical 'calorie' definitions exist (thermochemical 4.184 J; 'International Table' or IT calorie 4.1868 J), with the thermochemical version dominant in modern usage.
Calories are commonly used in nutrition, electrical billing, physics, and mechanical engineering.
Why Convert Kilojoules to Calories?
Converting energy between Kilojoules and Calories 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 Kilojoules to Calories?
A metric unit of energy equal to exactly 1,000 joules. To convert Kilojoules to Calories, multiply by 239.006. For example, 25 kJ equals 5975.14 cal.
How many Calories are in 1 Kilojoule?
There are 239.006 Calories in 1 Kilojoule.
How many Kilojoules are in 1 Calorie?
There are 0.004184 Kilojoules in 1 Calorie.
What is the formula for Kilojoule to Calorie conversion?
The formula is: multiply by 239.006. This means 1 kJ = 239.006 cal.
Is a Kilojoule bigger than a Calorie?
No. One Kilojoule is smaller than one Calorie because 1 kJ equals 239.006 cal, which is greater than 1.
When do you need to convert between Kilojoules and Calories?
The 'small' gram-calorie (also called thermochemical calorie), defined as exactly 4. Kilojoule and Calorie 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.