1000 calories (cal) 1 kilocalories (kcal). In common parlance, the two are mixed when one talks about 1000 calories, it is usually 1000 kilocalories or 1 million calories (that is about the energy content of a hearty lunch). Complicating the situation further is that some people shorten the kilocalorie with Cal, and some even mix it with the kilojoule (kJ), which is another unit of measure.