US Gallon (gal)
The US gallon, denoted as gal, is a unit of volume that equals approximately 3.785 liters. It comes from old English wine gallons and became official in the US in the 1800s. People in the US still use it extensively for fuel, beverages, and cooking. The US gallon is smaller than the British one, which leads to different numbers in global trade and when comparing fuel use. Although most countries use metric units, the US gallon remains a significant part of US life.
Cubic Inch (in³)
The cubic inch, symbol in³, is a US customary and imperial unit representing the volume of a cube with each side one inch in length. Its use dates back centuries in English measurement systems. Today, it is particularly significant in the automotive industry, where it historically defined engine displacement before metric liters became common. One cubic inch equals 16.387 milliliters, making it a small but practical unit for precision engineering, manufacturing, and certain niche applications.