Kilocalories (kcal)
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Equivalent energy
Accurate conversion between kilojoules (kJ) and calories (cal / kcal) for food, fitness and science
Convert kilojoules to calories instantly with precise calculations. Includes reverse calories to kilojoules conversion, full formula reference, food energy examples, and kJ/kcal comparison tables for 2026.
Professional energy conversion for nutrition, fitness, food science, and thermodynamics
Convert kilojoules to kilocalories using the exact formula: 1 kcal = 4.184 kJ. This is the thermochemical definition of the kilocalorie as standardised by the International System of Units. Our tool also outputs small calories (cal), joules (J), megajoules (MJ), and watt-hours (Wh), giving you a complete multi-unit energy breakdown in one step.
Switch seamlessly between kJ to kcal and kcal to kJ conversion modes. Whether you are reading a food label in kilojoules and need the calorie equivalent, or tracking your daily calorie intake and need to report it in kilojoules for a clinical or research context, both conversion directions are handled instantly from a single input value.
Essential for nutritionists, personal trainers, dietitians, food scientists, athletes, and anyone managing their diet in 2026. Food labels in Australia, New Zealand, and many European countries display energy in kilojoules, while the United States and fitness apps typically use kilocalories (Calories). Correct conversion ensures accurate dietary tracking and meal planning.
Select conversion direction and enter your energy value below
A kilojoule (kJ) is the SI (International System of Units) unit of energy equal to 1,000 joules. It is used in science, engineering, and nutrition across most of the world to measure energy content in food and beverages. A kilocalorie (kcal) — commonly called a "Calorie" (capital C) on food labels in the United States — is the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius at standard pressure.
The two units measure the same thing — energy — but use different scales. One kilocalorie equals exactly 4.184 kilojoules by the thermochemical definition. In everyday nutrition, when someone says they ate "2,000 calories," they mean 2,000 kcal, which equals 8,368 kJ. Understanding kilojoules to calories conversion is essential for reading food labels, planning meals, and tracking energy intake in 2026 regardless of which country's labelling system you are using. You can also explore BTU to Joules for other energy unit conversions.
1 kilocalorie (kcal) = 4.184 kilojoules (kJ) — This is the internationally standardised thermochemical value. On food labels, "Calories" (with a capital C) always means kilocalories. So a 250 Calorie snack contains 250 kcal = 1,046 kJ of energy.
The conversion between kilojoules and kilocalories uses a simple multiplication or division. The exact thermochemical factor is 4.184 kJ per kcal, which is the value used on food packaging, by health organisations, and in clinical nutrition worldwide.
Example 1: 500 kJ ÷ 4.184 = 119.5 kcal
Example 2: 300 kcal × 4.184 = 1,255.2 kJ
Bar heights are proportional to illustrate relative energy values
Use this quick-reference table to look up common kilojoules to calories conversions. All values use the exact thermochemical factor of 4.184 kJ per kcal. For values not shown, use the calculator above.
| Kilojoules (kJ) | Kilocalories (kcal) | Small Calories (cal) | Joules (J) | Watt-hours (Wh) |
|---|---|---|---|---|
| 1 kJ | 0.239 kcal | 239.006 cal | 1,000 J | 0.2778 Wh |
| 5 kJ | 1.196 kcal | 1,195 cal | 5,000 J | 1.389 Wh |
| 10 kJ | 2.390 kcal | 2,390 cal | 10,000 J | 2.778 Wh |
| 50 kJ | 11.95 kcal | 11,950 cal | 50,000 J | 13.89 Wh |
| 100 kJ | 23.90 kcal | 23,901 cal | 100,000 J | 27.78 Wh |
| 200 kJ | 47.80 kcal | 47,801 cal | 200,000 J | 55.56 Wh |
| 418.4 kJ | 100 kcal | 100,000 cal | 418,400 J | 116.2 Wh |
| 500 kJ | 119.5 kcal | 119,502 cal | 500,000 J | 138.9 Wh |
| 1,000 kJ | 239.0 kcal | 239,006 cal | 1,000,000 J | 277.8 Wh |
| 1,500 kJ | 358.5 kcal | 358,509 cal | 1,500,000 J | 416.7 Wh |
| 2,000 kJ | 478.0 kcal | 478,011 cal | 2,000,000 J | 555.6 Wh |
| 4,184 kJ | 1,000 kcal | 1,000,000 cal | 4,184,000 J | 1,162 Wh |
| 5,000 kJ | 1,195 kcal | 1,195,028 cal | 5,000,000 J | 1,389 Wh |
| 8,368 kJ | 2,000 kcal | 2,000,000 cal | 8,368,000 J | 2,324 Wh |
| 8,700 kJ | 2,079 kcal | 2,079,352 cal | 8,700,000 J | 2,417 Wh |
| 10,000 kJ | 2,390 kcal | 2,390,057 cal | 10,000,000 J | 2,778 Wh |
Understanding how kilojoules translate to calories becomes much easier when you relate the numbers to common foods and daily activities. The following examples give you an intuitive feel for the energy values in foods you eat every day.
A medium apple (approx. 182g) contains around 314 kJ, which equals approximately 75 kcal. Apples are a low-energy-density food, meaning they provide relatively few calories per gram while delivering fibre, vitamin C, and water — making them an excellent snack for weight management in 2026.
One slice of standard white bread (approx. 30g) contains around 318 kJ, equal to approximately 76 kcal. Wholegrain bread is similar in energy but higher in fibre and micronutrients. Most sandwiches with fillings range from 1,500 kJ (358 kcal) to 3,000 kJ (717 kcal) depending on ingredients.
One large boiled egg (approx. 50g) contains around 293 kJ, which equals approximately 70 kcal. Eggs are high in protein and healthy fats relative to their energy content. Two eggs for breakfast delivers around 586 kJ (140 kcal) — a relatively low-energy, high-satiety meal option.
A 30-minute jog at moderate pace (approximately 8 km/h) burns roughly 1,250–1,670 kJ (300–400 kcal) for an average 70 kg adult. Energy expenditure varies based on body weight, speed, terrain, and individual metabolism. This highlights why food energy labelling in kJ/kcal is important for activity-based planning.
A standard 50g milk chocolate bar contains approximately 1,100 kJ, equal to about 263 kcal. Dark chocolate (70%+ cocoa) is slightly lower at around 1,000 kJ (239 kcal) per 50g. Chocolate is energy-dense — a small portion provides a significant share of a typical daily intake of 8,700 kJ.
The average recommended daily energy intake is approximately 8,700 kJ for women and 10,500 kJ for men, corresponding to roughly 2,079 kcal and 2,510 kcal respectively. These are general guidelines — actual requirements vary based on age, body size, activity level, and metabolic rate as recommended by health authorities in 2026.
Different countries and industries use different energy units on food packaging and in health guidelines. Australia, New Zealand, and the European Union typically display food energy in kilojoules, while the United States, Canada, and most fitness applications use kilocalories (Calories). Being able to convert between them instantly eliminates confusion when comparing international products, following foreign recipes, or using apps calibrated in different units.
Our kilojoules to calories converter is designed to be fast and easy to use on any device including mobile phones and tablets. Follow these simple steps to get your result instantly.
The National Institute of Standards and Technology provides official definitions for all SI energy units including the joule, kilojoule, and calorie — used as the reference standard for this converter.
View NIST Reference →Need to convert to other energy units? Our full converter collection covers kJ to kcal, BTU to joules, and more — all free and mobile friendly for 2026.
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