Convert Kilocalories to Calories

About converting Kilocalories to Calories

Kilocalories (kcal) and Calories (cal) are both units of energy, so converting between them is a single multiplication: multiply your Kilocalories figure by 1,000. Ten Kilocalories comes to 10,000 Calories, and a hundred works out at 100,000 Calories.

Rule of thumb: going from Kilocalories to Calories multiplies, so the figure always grows — one Kilocalory is already 1,000 Calories. If your answer came out smaller, you have the conversion the wrong way round.

What is a Kilocalory?

A kilocalorie is a thousand small calories, and it is what people actually mean when they say "calories" about food. Every figure on a nutrition label, every count on a menu board and every target in a diet app is a kilocalorie, even where the label just prints "cal" — a 2,000-calorie day is 2,000 kcal, not 2,000 calories in the physicist’s sense. The convention of capitalising the food unit as Calorie was meant to mark that difference, but it survives mostly in textbooks. Most of the world prints both kJ and kcal on packaging; the United States prints calories alone, which keeps the ambiguity alive.

What is a Calory?

The calorie is the unit most likely to be misread, because there are two of them. The small calorie — the one this converter uses — is approximately the heat needed to warm a gram of water by one degree Celsius, and it is a tiny amount of energy. The "calories" printed on food labels are not these: a food Calorie, traditionally written with a capital C, is a thousand small calories, properly a kilocalorie. So a 2,000-calorie daily diet is really about 8.4 million small calories. Several slightly different calories were defined historically; the thermochemical calorie used here is fixed at exactly 4.184 joules.

To put both in perspective: a plain bagel runs to roughly 250 kilocalories, while an apple holds roughly 95,000 small calories.

The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Calories to Kilocalories converter, or browse all Energy converters.