Letter "K" after numbers or in measurements March 3, 2011July 18, 2017 / thewanderingitinerant The letter “K” placed after numbers such as in 7K calories refers to kilos. This unit prefix denotes multiplication of the unit by one thousand. It can also be noticed in other measurements such as in weight. Share this:TwitterFacebookMoreEmailLinkedInPinterestLike this:Like Loading... Related