Calorie & Kilojoule Calculator
Convert kilojoules to calories and calories to kJ.
Convert kilojoules and calories
Type in either box and the other updates.
1 Calorie (kcal) = 4.184 kJ. “Calories” with a capital C on food labels means kilocalories.
Result
2,000 kJ = 478 Cal
Compared with 8,700 kJ (2,079 Cal), the average adult daily intake used on Australian food labels. Your own needs will differ — see the TDEE calculator for personal daily needs.
Quick reference
| kJ | Cal (kcal) | % of 8,700 kJ |
|---|---|---|
| 2,000 | 478.0 | 23% |
| 2,080 | 497.1 | 24% |
| 2,200 | 525.8 | 25% |
| 2,500 | 597.5 | 29% |
| 4,000 | 956.0 | 46% |
| 5,000 | 1,195.0 | 57% |
| 6,000 | 1,434.0 | 69% |
| 8,700 | 2,079.3 | 100% |
| 10,000 | 2,390.1 | 115% |
| Cal (kcal) | kJ | % of 8,700 kJ |
|---|---|---|
| 100 | 418.4 | 4.8% |
| 500 | 2,092.0 | 24% |
| 1,000 | 4,184.0 | 48% |
| 1,500 | 6,276.0 | 72% |
| 2,000 | 8,368.0 | 96% |
| 2,500 | 10,460.0 | 120% |
| 3,000 | 12,552.0 | 144% |
Kilojoules to Calories Converter
This kilojoules calculator converts kJ to calories and calories to kJ as you type. Enter an amount in either box and the other updates straight away, along with what share of the 8,700 kJ average daily intake it represents. If you have a food label in front of you, the label helper works out the energy in what you actually ate from the per-100 g or per-serve figure. It is a simple calorie converter for the units you see on Australian packaging, menus and fitness apps.
The Conversion Formula
Calories (kcal) to kJ = kcal × 4.184
1 kilocalorie is defined as exactly 4.184 kJ, so the conversion has no rounding error until you choose how many decimals to display.
Energy eaten from a label = energy per serve × servings (or energy per 100 g × grams ÷ 100)
Worked Example: 2,000 kJ and 500 kcal
2,000 kJ to calories: 2,000 ÷ 4.184 = 478.01, so 2,000 kJ is about 478 Cal (kcal). As a share of 8,700 kJ that is 2,000 ÷ 8,700 = 23%.
500 kcal to kJ: 500 × 4.184 = 2,092 kJ, which is about 24% of 8,700 kJ.
Reading a label: a snack lists 1,800 kJ per 100 g with a 30 g serve. One serve is 1,800 × 30 ÷ 100 = 540 kJ (129 Cal). Eating two serves is 1,080 kJ, or 258 Cal, about 12% of the 8,700 kJ reference.
Calorie, Calorie and kcal: Cal vs cal
Strictly, a calorie (small c) is a very small unit of energy, about 4.184 joules. A kilocalorie (kcal) is 1,000 calories, and a food “Calorie” with a capital C means the same as a kilocalorie. In everyday speech and on nutrition apps, “calories” almost always means kilocalories, which is what this converter uses. The headline shows them as “Cal” and the box is labelled kcal to keep that clear.
Why Australia Uses Kilojoules, and What 8,700 kJ Means
The joule is the standard metric unit of energy, and Australian food labelling rules generally require the energy content of packaged food to be shown in kilojoules, so that is the number you will see in the nutrition information panel. Labels also use 8,700 kJ (about 2,079 Cal) as the average adult daily intake when they show a percentage daily intake. It is a yardstick that makes products comparable, not a personal target: someone who is smaller, older or less active may need less, and someone who is larger or very active may need more.
Frequently Asked Questions
- How many calories is 2000 kJ (2000kj to cal)?
- 2,000 kJ is about 478 calories (kcal), because 2,000 ÷ 4.184 = 478.01. When people search for 2000kj to cals or 2000kj to calories they almost always mean the food Calorie, which is the same as a kilocalorie. Going the other way, 2,000 Calories is 8,368 kJ.
- How many calories is 8700 kJ?
- 8,700 kJ is about 2,079 calories (8,700 ÷ 4.184 = 2,079.3). It is the average adult daily intake that Australian food labels use to work out the percentage daily intake (%DI) figure, so 8,700 kJ is 100% on that scale. It is a reference value for comparing foods, not a recommendation for any one person.
- What is 5000 kJ in calories?
- 5,000 kJ is about 1,195 calories (5,000 ÷ 4.184 = 1,195.0). That is roughly 57% of the 8,700 kJ label reference, which is useful when you are comparing a meal or a day of eating against the label scale.
- What are 2080 kJ, 2200 kJ and 2500 kJ in calories?
- 2,080 kJ is 497.1 calories, 2,200 kJ is 525.8 calories and 2,500 kJ is 597.5 calories. Each is the kJ figure divided by 4.184. A quick mental estimate is to divide the kilojoules by 4, which is slightly high, or to divide by 4.2 for a closer answer.
- How do I convert calories to kJ, such as 500 calories to kJ or 3000 calories to kJ?
- Multiply the calories (kcal) by 4.184. So 500 calories is 500 × 4.184 = 2,092 kJ, and 3,000 calories is 12,552 kJ. The calories to kJ conversion is exact, because 1 kcal is defined as 4.184 kJ.
- How many kilojoules are in 100 calories?
- 100 calories (kcal) is 418.4 kJ. For other small amounts, 50 calories is 209.2 kJ and 200 calories is 836.8 kJ. Multiply the calories by 4.184 for any other figure.
- What is the difference between a calorie, a Calorie and a kcal?
- A small-c calorie (cal) is a tiny unit, about 4.184 joules. A kilocalorie (kcal) is 1,000 of them, and a capital-C Calorie (Cal) is another name for a kilocalorie. When food is described as having 200 calories, it means 200 kcal, which is 836.8 kJ.
- Why does Australia use kilojoules instead of calories?
- The kilojoule is the metric (SI) unit of energy, and Australian and New Zealand food labelling rules generally require energy to be shown in kilojoules. Many labels and menus show calories as well, and this kilojoules calculator lets you move between the two. Since the conversion is a fixed factor of 4.184, the numbers are always directly comparable.
- Is 8700 kJ how much I should eat each day?
- Not necessarily. 8,700 kJ is an average used so that labels can show how much a serve contributes to a typical adult's day. Real energy needs depend on age, sex, body size, activity and health, and are often higher or lower. For a personalised estimate see the TDEE calculator, and speak with a GP or an accredited practising dietitian before changing how you eat.