Kilojoules to Calories converter
kJ to food Calories (kcal), and back
Type in either box. The example turns 8,700 kJ, the average adult daily intake used on Australian labels, into Calories.
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- Calories by the Australian and NZ label rule (÷ 4.18)
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- Small calories (cal)
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The rule
A food Calorie, written with a capital C, is a kilocalorie: 1,000 small calories. One small calorie is defined as exactly 4.184 joules (NIST Special Publication 811), so one Calorie is exactly 4.184 kilojoules. Kilojoules to Calories: divide by 4.184. Calories to kilojoules: multiply by 4.184.
Worked example
8,700 kJ ÷ 4.184 = 2,079.35 Calories. Going back, 2,079.35 × 4.184 = 8,700 kJ. The 8,700 kJ figure is the average adult daily intake that Australian and New Zealand labels use for their percentage figures.
The label rule in Australia and New Zealand
The Food Standards Code (Schedule 11, section S11—2) tells food companies to work out Calories as kilojoules divided by 4.18, not 4.184. The answer card shows both. The difference is about 0.1%: 8,700 kJ is 2,081.34 Calories by the label rule. If you are checking a label, use the label figure; for anything else, use the exact one.
Which calorie
Australian and New Zealand labels show kilojoules first, often with Calories beside them. US labels show only Calories. When a diet plan says "2,000 calories" it means 2,000 kilocalories. For other energy units, such as kilowatt-hours, see the unit converter.
A quick check in your head
Divide kilojoules by 4 and take off a little: 1,000 kJ is about 250, exactly 239 Calories.
Rounding
The answer is worked out from the exact definition, then shown to 4 decimal places (6 significant figures for numbers below 1). It says "exactly" only when nothing was rounded.
Kilojoules to Calories chart
Worked out from the exact definitions and rounded as above.
| Kilojoules | Kilocalories (food calories) |
|---|---|
| 100 kJ | 23.9006 kcal |
| 200 kJ | 47.8011 kcal |
| 250 kJ | 59.7514 kcal |
| 400 kJ | 95.6023 kcal |
| 500 kJ | 119.5029 kcal |
| 600 kJ | 143.4034 kcal |
| 800 kJ | 191.2046 kcal |
| 1,000 kJ | 239.0057 kcal |
| 1,500 kJ | 358.5086 kcal |
| 2,000 kJ | 478.0115 kcal |
| 4,184 kJ | 1,000 kcal |
| 5,000 kJ | 1,195.0287 kcal |
| 6,000 kJ | 1,434.0344 kcal |
| 8,700 kJ | 2,079.3499 kcal |
| 10,000 kJ | 2,390.0574 kcal |
| Kilocalories (food calories) | Kilojoules |
|---|---|
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 150 kcal | 627.6 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1,046 kJ |
| 300 kcal | 1,255.2 kJ |
| 400 kcal | 1,673.6 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 1,500 kcal | 6,276 kJ |
| 2,000 kcal | 8,368 kJ |
| 2,500 kcal | 10,460 kJ |