Kilojoules vs calories
Kilojoules and calories both measure food energy. One dietary calorie is 4.184 kilojoules, so a 2,000 Cal day is an 8,368 kJ day. Australian labels, menu boards and dietary guidelines use kilojoules; most fitness content online uses calories because it is American.
| Kilojoule (kJ) | Calorie (Cal) | |
|---|---|---|
| Unit type | Metric (SI) | Imperial-era, still common |
| Used on Australian labels | Yes, required | Optional, often shown alongside |
| Used on chain menu boards in Australia | Yes | No |
| 1 of this equals | 0.239 Cal | 4.184 kJ |
| Typical adult day | 8,700 kJ | 2,079 Cal |
The quick conversions worth memorising
- 1,000 kJ is about 239 Cal.
- 2,000 kJ is about 478 Cal.
- 8,700 kJ is about 2,079 Cal.
- To go from kJ to Cal, divide by 4. Then take off 4%.
Why the unit you track in matters
Every conversion is a chance to give up. If the packet says 1,450 kJ and your app wants calories, you either do the maths or you guess, and guessing is what breaks tracking in the first fortnight. Tracking in kilojoules keeps the number identical from the label to the log.
It also makes menu boards useful. When a board says 2,700 kJ for a burger and your day is 9,000 kJ, you can do that division standing at the counter. Converting to calories first is the reason most people never bother.
Stop guessing the number
OzCal logs this in about five seconds: snap it, scan the barcode or say it. Kilojoules the way the label shows them, on 26,600 verified Australian foods.
Common questions
Are kilojoules and calories the same thing?
They measure the same thing, food energy, in different units. One dietary calorie equals 4.184 kilojoules.
Which is bigger, a kilojoule or a calorie?
A calorie is bigger. Any food shows a larger number in kilojoules than in calories, which is why 2,000 Cal looks small next to 8,368 kJ.
Why do Australian labels use kilojoules?
Australia is metric, so the joule is the official unit of energy. Packaged food panels and chain menu boards use kilojoules by law.
Should I track in kJ or Cal?
Track in the unit your labels use. In Australia that is kilojoules, which removes a conversion step every time you log.
Do New Zealand labels use kilojoules too?
Yes. Australia and New Zealand share food standards through FSANZ, so both use kilojoules on packaged food.
Keep reading
Citing this page. OzCal (2026). "Kilojoules vs Calories: The Australian Guide | OzCal". Retrieved from https://ozcal.com.au/kilojoules-vs-calories. Last updated 2026-09-15. Figures are per the serve stated in each row, converted at 1 Cal = 4.184 kJ. A plain-text version of this page is available at https://ozcal.com.au/kilojoules-vs-calories.md.