What’s the difference between kcal and calories

            What’s the difference between kcal and calories

Energy is measured in calories. Calories refer to the amount of energy in foods and beverages or the amount of energy you burn exercising.

Energy can also be measured in Kilocalories (Kcal) and Kilojoules (KJ) which gets some people confused.

This article explains what calories and kilocalories are, the difference between the two as well as how to convert them.

The difference between kcal and calories

Calories are quantified as “large” or “small”. If the “c” in calories is uppercase, it indicates a large calorie and if it’s lowercase, it indicates a small calorie.

A large calorie estimates the amount of energy required to raise the temperature of 1kg (2.2 pounds) of water by 1oc (34oF) while, a small calorie estimates the amount of energy it takes to raise the temperature of 1 gram (0.035 ounces) of water by 1oc (34oF).

From this definition, 1 large calorie equals 1,000 small calories as 1kg equals 1,000 grams.

The term kilocalories, the prefix “Kilo” meaning 1,000 was created to refer to a large calorie.

The term small calorie is rarely used today outside of physics and chemistry research, instead, the terms calories, capitalized or not and Kcal are used interchangeably and refer to the same amount of energy in relation to food or energy burned during exercise.

In nutrition, 1 kilocalorie equals 1 calorie. You don’t need to convert them.

Calories may also be expressed as kilojoules (KJ), One calorie (Kcal) equals 4.18KJ or 4,184 joules (J)

How to covert them

To convert from calories to KJ, multiply calories by 4.18. Conversely, to convert from KJ to calories, divide KJ by 4.18.

Below is a list of countries and which label they use for energy.

  • United states Calories
  • Canada Calories
  • European Union (EU) KJ and Kcal
  • Australia and New Zealand Kj or both KJ and Kcal
  • China KJ

To determine the number of calories a food or beverage contains, the manufacturers calculated this based on the amount of energy supplying nutrients it contains. The 3 main energy- supplying nutrients are protein, carbs, and fats.

Protein and carbs each provide about 4 calories (167kj) per gram while fat provides 9 calories per gram (37.6kj)

Manufacturers round to the nearest 1 gram increment, so if you were to quantify the number of calories or KJ from each of the macronutrients, they may add up to be slightly different than the number listed on the nutrition labels.


Calories are a measure of energy in nutrition and exercise. The “calorie” we refer to in food is actually kilocalorie. One (1) kilocalorie is the same as one (1) Calorie (uppercase). A kilocalorie and calorie are used interchangeably and refer to the same amount of energy and may also be measured in KJ, with one calorie (Kcal) equaling 4.18KJ.