Calorie Calculator: kcal to kJ and kJ to kcal Converter

Calorie Calculator: kcal ↔ kJ Converter

To be honest, many of us living in kJ countries still think in Calories. I often find myself doing the math in my head when reading food labels.

Sometimes my brain is tired or I want to be precise—so it’s nice to have a simple calculator to do the work for me. If you’ve ever tried to make sense of an international food label, this calorie converter gives you exact values in seconds.

How to Use This Calorie Converter

Simply enter your number below to switch between:
Calories (kcal)
Kilojoules (kJ)

Why Do We Need a Calorie Calculator?

While science and countries like Australia and New Zealand officially use kilojoules (kJ), much of the world—including the United States, Canada, and parts of Asia—still use Calories (which are technically kilocalories or kcal). Because we’re often working across different systems, it helps to have a reliable way to convert between them.

Calories (kilocalories / kcal) vs Kilojoules (kJ)
Around the World

The use of Calories (kilocalories / kcal) versus kilojoules (kJ) varies by region and reflects a mix of regulation and familiarity.

United States

The United States uses Calories (kilocalories / kcal) on Nutrition Facts labels, with no requirement to display kilojoules (kJ).

Canada

Canada also uses Calories (kilocalories / kcal) on food labels, despite being a metric country, and does not typically display kilojoules (kJ).

Japan

Japan uses Calories (kilocalories / kcal) on food labels. The unit is usually written as “kcal,” and kilojoules (kJ) are generally not used in consumer-facing nutrition information.

European Union and United Kingdom

Food labels must display both kilojoules (kJ) and Calories (kilocalories / kcal), with kJ typically listed first. However, most people still think in Calories (kcal).

Asia and Latin America

Many countries in these regions use Calories (kilocalories / kcal) on food labels, although some also include kilojoules (kJ). Practices vary, but consumer familiarity tends to favour Calories (kcal).

The “Kilojoule Countries”

Australia and New Zealand emphasise kilojoules (kJ) on food labels, although Calories (kilocalories / kcal), may sometimes be included.

Why the Divide?

Familiarity: People have an intuitive feel for calories
Numerical scale: Kilojoules use larger numbers (1 kcal = 4.184 kJ), which can feel less intuitive

What Do All the Terms Mean?

Calories (Cal)
• Used on food labels (especially in the US)
• Always means kilocalories (kcal)

kcal (kilocalories)
• Scientific term for food energy
• 1 kcal = 1 Calorie

kJ (kilojoules)
• Metric unit of energy
• Used in Australia, New Zealand, and required in the EU
• 1 kcal = 4.184 kJ

cal (lowercase)
• Small calorie (scientific unit)
• 1 kcal = 1000 cal
• Rarely used in nutrition

“C” – If you see “C” on packaging or apps, it almost always means Calories (kcal)
• Informal abbreviation for Calories (kilocalories / kcal)
• Not standardised or officially recognised
• Can be confusing and is best avoided