Ainonymity Calorie Counter · Kilojoules
Kilojoules and calories: a kJ calorie counter, explained.
Published
In Australia and New Zealand, food energy is printed in kilojoules, and across Europe and the UK kilojoules sit beside calories on every label. Ainonymity Calorie Counter works in kilojoules too — every meal, every chart and your daily target — with one switch in Settings.
Converting kJ to calories
One kilocalorie — what everyday speech calls a calorie — is 4.184 kilojoules. That is the exact factor the app uses in both directions. To turn kJ into calories, divide by 4.184; to turn calories into kJ, multiply.
| Calories (kcal) | Kilojoules (kJ) |
|---|---|
| 100 | 418 |
| 239 | 1,000 |
| 500 | 2,092 |
| 2,000 | 8,368 |
| 2,079 | 8,700 |
A rough rule for reading a label in the shop: kilojoules are a little over four times the calorie figure. The European reference intake of 8,400 kJ is the 2,000 kcal row above, rounded.
Who prints kilojoules on the label
Australia and New Zealand: kilojoules first
Food Standards Australia New Zealand, the regulator for both countries, sets the nutrition information panel. It declares energy in kilojoules, or in kilojoules and kilocalories together — so kJ is the figure every packet carries, and calories are the optional extra.
Many panels also carry a percentage daily intake column. Those percentages are calculated against a reference average adult diet of 8,700 kJ, and a panel that shows them has to say so in those words.
The European Union and the UK: both, side by side
Under the EU’s food information regulation, which the UK kept in its own law, a nutrition declaration gives energy in kilojoules and in kilocalories, per 100 g or 100 ml. Where a label shows percentages, they are of a reference intake of an average adult, 8,400 kJ / 2,000 kcal.
The United States and Canada: Calories
North American labels print energy as Calories — the same kilocalorie, with a capital C.
The 8,700 and the 8,400 are both labelling references, so every packet in a country uses the same yardstick — fixed numbers for comparing products, and your own needs may be well above or below them.
How the app handles kilojoules
- One switch. Settings → Energy Unit, kcal or kJ. Meals, the daily ring, the trend charts and the PDF report all follow it.
- Your target is a round kilojoule figure. The app saves the daily target twice, as a whole multiple of 50 in each unit, so a kJ user sees a clean number they chose rather than 8,368.
- Switching changes the display, and only the display. Every meal is stored once, in a single unit, and converted as it is shown — so moving between kcal and kJ leaves every logged meal exactly as it was.
The ingredient search includes AUSNUT, the Australian food composition data published by the same regulator — see where the food data comes from.
Questions about kilojoules
How many kilojoules are in a calorie?
4.184. One food calorie — strictly, a kilocalorie — is 4.184 kilojoules, so 1,000 kJ is about 239 calories.
How many kilojoules should I eat a day?
It depends on your age, size, sex and how active you are. The 8,700 kJ on Australian and New Zealand labels and the 8,400 kJ on European ones are references for comparing products, and the app works out a personal starting figure from your own details instead — here is how that target is calculated.
Can I switch between kJ and calories at any time?
Yes. Switching changes how figures are shown, and every logged meal stays as it was. Your daily target keeps its own round figure in each unit.
Is a kJ calorie counter any different from a calorie counter?
The maths is the same, because the two units measure the same energy. What differs is whether the app shows you the unit on your food labels — this one does, in either.
Where these figures come from
- Food Standards Australia New Zealand — Nutrition information panels — energy declared in kilojoules, or in kilojoules and kilocalories.
- Food Standards Australia New Zealand, June 2015 — Evaluation of Labelling Review Recommendation 17 — percentage daily intakes “based on an average adult diet of 8700 kJ”.
- Regulation (EU) No 1169/2011 on the provision of food information to consumers — Article 32 and Annex XV, energy in kJ and kcal; Annex XIII Part B, the 8 400 kJ / 2 000 kcal reference intake.
- The same regulation as retained in UK law, Annex XV — legislation.gov.uk.
- 4.184 kJ per kilocalorie — the thermochemical calorie, and the factor the app uses.
See it working in kilojoules — have a look at Ainonymity Calorie Counter, or read why calorie apps disagree.