How many fluid ounces are there in one gallon?

One gallon is equal to 128 fluid ounces. This relationship is derived from the fact that a gallon consists of four quarts and each quart contains 32 fluid ounces. When you multiply the number of quarts in a gallon (4) by the number of fluid ounces in a quart (32), you arrive at the total for one gallon:

4 quarts x 32 fluid ounces per quart = 128 fluid ounces.

This conversion is commonly used in cooking, liquid measurements, and various industries, making it essential knowledge.