Canny Converter is a little App that lets you convert from one unit of measure to another. The user interface gives you access to the tools you need quickly while also letting you go "deeper" if you want to. Canny Converter will always be a free App with no ads, no trial period and it doesn't need any weird permissions.
While some other conversion Apps are more comprehensive in the number of units of measure they offer, the developer of Canny Converter decided to only provide the measures that most people might use in their everyday lives. So, while you won't see Parsecs, Bushels or Gigapascals, you will get an interface that's easy to navigate without lots of page-switching and scrolling of long lists.