This is a list of the fastest-selling product superlatives. The definition of "fastest-selling" typically refers to sales results in the first week of a product's release, (i.e., which product had the biggest launch). Sometimes, rather than comparing sales figures relative to time, the target to be reached is fixed (e.g. sales at 5 million units), and the comparison is based upon how many weeks it takes to reach it (e.g. 52 weeks vs. 56 weeks).