Imperial Gallon (imp gal)
The imperial gallon, shown as imp gal, is a British unit equal to 4.54609 liters. It came from English wine and drink measures in the 1800s and became official in 1824. The imperial gallon was used throughout the British Empire and is still used in the UK and some other countries for fuel and beverages. The liter is now used almost everywhere, but the imperial gallon still exists because of custom and local use.
US Quart (qt)
The US quart, symbol qt, equals 1/4 of a US gallon, or about 0.946 liters. Originating from English quart measurements, it was standardized in the US system in the 19th century. Quart is frequently used in American cooking, grocery packaging, and automotive fluids. While less common internationally due to the adoption of the metric system, the quart remains an important household and commercial measure in the United States.