Difference Between Fluid Ounce and Weight Ounce

What is the Difference Between Fluid and Weight Ounce?

First of all, many people would like to go back in time and change sharing the same name for different systems of measurements.

Ounce to measure both volume and weight? Yes, it is confusing. However, it's better to learn the difference rather than googling it each day.

The key difference behind the fluid ounce and weight ounce is,

Ounces (weight ounces) are a unit of weight measurement and

Fluid Ounces are a unit of volume measurement.

To understand what to use on different occasions, we can separate ingredients needed to be measured into two different categories.

Dry ingredients

Rice, Flour, Sugar, Pasta, Oats, Cereal, Beans, etc.

Dry measuring cups

Dry ingredients are measured in ounces and should be measured using dry measuring cups or on a scale. Dry measuring cups are made out of plastic or steel and come in sets of four cups including 1 cup, 1/2 cup, 1/3 cup, and 1/4 cup sizes.

Wet ingredients

Water, Milk, Oil, Honey, Cream, etc.

Liquid measuring cups

Wet ingredients are measured in fluid ounces and should be measured using measuring cups.
Liquid measuring cups are made out of glass and come in sets of three cups including 1 cup, 2 cups, and 4 cups sizes. The measurements are marked in cups, fluid ounces, and milliliters. 

In mathematics, we actually call the weight ounce a dry ounce. As per the abbreviation let's use,

dry ounce = oz.

and

fluid ounce = fl. oz.


dry oz. -> 1 oz. = 1/16 lb (Here, when we're dealing with dry ounces we just say "ounce")

fl. oz. -> 1 fl. oz. = 1/16 pint


When dealing with volume measurements using fluid ounces and pints we shall know the following conversions.

8 fl. oz. = 1 cup

1 pint = 2 cups

1 quart = 2 pints

1 gallon = 4 quarts


Now, as far as weight goes if we're converting one ounce to the metric system,

1 oz. = 28.3495 g

and,

1 fl. oz. = 29.573 ml

If you are further interested you can read about the metric system in the USA  and volume metric measurements. 

When you know these basic conversions, you can easily switch between different measuring systems, multiply or cut down recipes.

However, in some recipes, there are clear instructions that all the ingredients should be measured by weight on a scale where dry or liquid measuring cups are not required. Therefore, make sure you read all the instructions clearly before jumping into the ingredient measurements. And always remember coffee mugs, teacups, or mugs are not precise measuring cups. Ultimately, you should really consider buying a decent digital scale.