Milliliter (mL)
The milliliter, symbol mL, is a metric unit of volume equal to one-thousandth of a liter. Introduced alongside the metric system in the late 18th century in France, it provides a practical measure for small liquid quantities, such as in cooking, pharmaceuticals, and laboratory work. One milliliter of water is approximately equal to one cubic centimeter, making conversions between mass and volume straightforward for water-based liquids. The milliliter’s adoption worldwide has standardized recipes, measurements, and scientific experiments, allowing for precision and consistency across countries.
Gallon (US)
The US gallon, symbol gal, equals 4 quarts, 8 pints, or 128 fluid ounces (~3.785 liters). Its origins trace to English wine and ale measures but were standardized in the US in the 19th century. Gallons are used for beverages, fuel, and large-volume recipes. While metric liters are the dominant unit of measurement in most countries, gallons remain widely used in the United States for everyday and industrial liquid measurements.