How many fl oz in one cup?

Answer 1

The unit ounce has two different meanings one means weight and the other fluid volume. For example, there are 16 ounces in a pound and 32 ounces in a quart.

Even within the two meanings it's ambiguous.

For both weight and volume there are several different standards.

When referring to weight the two most common are (thought there are several more):

avoirdupois ounce (the commonly used measure)

troy ounce (used for precious metals - gold, silver, etc)

When referring to volume the three most common are:

U.S. customary fluid ounce (like a measuring cup)

U.S. food labeling fluid ounce

Imperial (British) fluid ounce

But, the differences are relatively small, and for common use the standards within each category (weight or volume) are pretty much interchangeable.

However, there is little relationship between the weight and volume units. For example, a fluid ounce of Mercury weighs much (14 times?) more than a fluid ounce of water.

The units were originally chosen to be the same for water. That is, a fluid ounce of water was to weigh one ounce. But, when this was done methods were not as precise as they are today, so an ounce of water doesn't weigh exactly one ounce -- but it's quite close.

Answer 2

A fluid ounce is a unit of volume. An ounce is a unit of weight. The difference will vary by substance.

Answer 3

There are 40 ounces to an imperial quart, and 32 ounces to a US quart.

Answer 4

There are 32 fluid ounces in a quart. 16 fluid ounces in 1 pint and 2 pints in a quart.

Answer 5

1 Fluid Ounce is equivalent to 1 fl oz.

Answer 6

Eight.