It's an imperial gallon[1]. As to why it's an imperial gallon, or what an imperial gallon really is, or who uses it--don't ask me. I'm a very metric sort of pe

It's an imperial gallon[1]. As to why it's an imperial gallon, or what an imperial gallon really is, or who uses it--don't ask me. I'm a very metric sort of person :P. [1]: https://www.google.com/search?q=imperial+gallon+in+cubic+decimeter https://www.google.com/search?q=imperial+gallon+in+cubic+dec...