system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are calories shown in (kcal) and not (cal) when K is shorthand for Kilo (1000) ?

So for example, I'm looking at a pack of sausages, the text says "reference intake of an average adult is 8400kJ / 2000 kcal - but I am reading this as 2 million calories, since K is short for kilo which means 1000?
gpt
People use Calorie (note the capital) and Kilocalorie interchangeably. The calorie (small c) is 1/1000 of a Calorie.

So it's both. 2000 big Calories (which is the actual measurement everyone is used to dealing with), 2 million small calories (which is arguably more true to the definitions, but nobody outside of particularly ornery chemists has any real use for the unit). Since nobody really uses the small calorie for anything, people don't know/forget they're two different things and also get sloppy about distinguishing between the two.