Convert BTU to Kilocalories

About converting BTU to Kilocalories

BTU (BTU) and Kilocalories (kcal) are both units of energy, so converting between them is a single multiplication: multiply your BTU figure by 0.2522. Ten BTU comes to 2.5216 Kilocalories, and a hundred works out at 25.2164 Kilocalories.

Rule of thumb: going from BTU to Kilocalories divides, so the figure always shrinks — it takes about 3.9657 BTU to make a single Kilocalory. If your answer came out bigger, you have the conversion the wrong way round.

What is a BTU?

The BTU is the heat needed to raise one pound of water by one degree Fahrenheit — and there is no single BTU. Water takes slightly different amounts of heat to warm depending on the temperature it starts from, so several definitions exist (thermochemical, International Table, 39 °F, 59 °F, 60 °F and others), differing from one another by a fraction of a percent. This converter uses one common value, so treat the result as convention-dependent rather than absolute. In the US it is the unit of heating and cooling capacity, though air conditioners are really rated in BTU per hour and the "per hour" is routinely dropped in marketing.

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.

To put both in perspective: a wooden kitchen match releases roughly one BTU, while a plain bagel runs to roughly 250 kilocalories.

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