Pocket Cal/kJ

Calories to kilojoules, and back.

Type a number and see both. Then see what it means: the food it equals and the walk it takes.

iPhone and iPadApp StoreAndroidGoogle Play

4.6 stars. 4.6 from 668 ratings on the Australian App Store, as at November 2026. Live since 2011 on iOS and Android.

Calorie and kilojoule converter

Example only. Type a number or use the keypad. Tap either box to convert from that unit.

1 Cal = 4.184 kJ. A Calorie here is a food Calorie (kcal).

The number, then what it means

A kilojoule figure on a label says little by itself. Pocket Cal/kJ turns it into things you can picture.

Food comparisons

Enter an amount and see foods that come close, as the servings a person would actually eat. Pick from 153 everyday foods.

  • Serving bars show how much of one serving your number covers, up to two.
  • Comparisons are everyday estimates, not nutrition labels.
Convert screen showing 250 Calories as 1,046 kilojoules, with a close food match and a walking guide of 28 to 77 minutes
Convert screen in dark mode showing 490 Calories as 2,050 kilojoules

Exercise and walking

See how long an activity takes to match your number, or how much energy a number of minutes uses.

  • The walking guide is free. Without your weight it shows a range for a reference adult. Add your weight and it gives one figure.
  • Pro adds 29 more exercises.
All exercises list for 250 Calories, with walking at 28 to 77 minutes

Four calculators, one control

Convert, Portion, Exercise to energy and BMI sit behind one radial control, so each is a tap away from the converter.

  • Portion: enter the energy per 100 g or 100 mL from a label and the amount you are having.
  • Body overview: BMI and age are free. The deeper report is in Pro.
  • BMI is a screening measure, not a diagnosis.
The radial control open over the Convert screen, offering Exercise, Portions and BMI
Portion calculator: 400 kJ per 100 g and 75 g gives 300 kJ or 71.7 Cal

Look up a value: kilojoule and Calorie conversions, the food list and exercise energy.

Also in the app: 12 languages, and the same app on iOS and Android. Screens above are captured from version 4.0 builds on iOS.

Five themes. Pick one and this page follows.

Each theme has a light and a dark version and a matching app icon. The colours here are the app's own. Ocean Baths is the default.

One purchase. No subscription.

Pro is a single payment. There is no monthly or yearly charge, and no ads once you have it.

  • 29 more exercisesExercise comparisons beyond the free set.
  • Deeper body reportResting and daily energy estimates and heart rate references, built on the BMI and age overview that stay free.
  • No adsPro removes ads from the whole app.

In development

Two things are being built. Neither is in the app yet.

Not available yet

Label Lens

A nutrition label scanner for Pocket Cal/kJ. Details will follow when it is closer to release.

Not available yet

Watch app

A watch app for Pocket Cal/kJ. Details will follow when it is closer to release.

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Questions

Why kilojoules?

Food labels in Australia, New Zealand, the UK and the EU give energy in kilojoules, and in the UK and EU also in kcal. Recipes, fitness apps and a lot of diet advice use Calories. Pocket Cal/kJ moves between the two so you do not have to do the sum.

How does the conversion work?

One Calorie (a food Calorie, also written kcal) is 4.184 kilojoules. To go from Calories to kilojoules, multiply by 4.184. To go the other way, divide by 4.184.

For example, 820 Cal is 3,430.88 kJ. Results are shown to 2 decimal places. The converter on this page runs the same conversion code as the app.

Is it free?

Yes. Pocket Cal/kJ is free and shows ads. Pro is a one-off purchase that removes the ads and adds more. It is not a subscription.

What does Pro add?

29 more exercises, the deeper body report (resting and daily energy estimates and heart rate references), and no ads. Walking, the BMI and age overview, the converter and the food comparisons stay free.

What about privacy?

The privacy policy for the app is being updated. Until then the current policy is at https://darkice.au/pocket-cal/privacy. This website does not use analytics or advertising scripts, and the Notify me form below does not send or store anything yet. In the app, a converter lookup is not recorded as food eaten or exercise done.