In the world of measuring liquids, one frequently encountered question revolves around the conversion between gallons and cups. A gallon, abbreviated as gal, is a larger unit of liquid volume in the US customary system. One gallon is equivalent to 128 fluid ounces or 3.785 liters. On the other hand, a cup, abbreviated as c, is a smaller unit of volume. A single cup contains 8 fluid ounces or 236.59 milliliters. Therefore, a gallon of milk contains 16 cups, providing a convenient conversion factor for recipes and everyday measurements.