American Standard System of Measurement

This page discusses the American Standard System of Measurement.

Pharmacy Technicians need to be familiar with several systems of measurement to perform the everyday tasks required in a pharmacy.

The American Standard system of measurement is important because it will be the one most familiar to your customers.

And it's important to be able to explain dosage information in terms they can easily understand and recall later.

The American Standard system is also referred to as the Household system.

Volumes of liquid are measured in:



Fluid Ounces





Conversions within the Household system are as follows:

3 teaspoons = 1 tablespoon (one-half of a fluid ounce)

2 tablespoons = 1 fluid ounce

8 fluid ounces = 1 cup

2 cups = 1 pint (16 fluid ounces)

2 pints= 1 quart (32 fluid ounces)

4 quarts = 1 gallon (128 fluid ounces)

Weight is measured in:



There are 16 ounces to a pound.

Length is measured in:





12 inches = 1 foot

3 feet = 1 yard

1760 yards = 1 mile(5280 feet)

The most common calculations you'll need to make will be converting a metric measurement into an American standard measurement.

Kilograms into pounds or milliliters into teaspoons for example.

Here are the most common Metric to Standard conversions that you will encounter.

1 kilogram (1000 grams) = 2.2 pounds

3.8 liters (3800 milliliters) = 1 gallon

5 milliliters = 1 teaspoon

15 milliliters = 1 tablespoon

29.6 milliliters = 1 fluid ounce

It's important to memorize these conversions and also to understand which unit is larger.

This makes it easy to double check a conversion to ensure you did it correctly.

For example, we know that a kilogram weighs more than a pound.

So after converting 5 kilograms, we can look at our answer(11 pounds) and understand that it looks correct.

Teaspoons and tablespoons from milliliters is another common conversion.

Most liquids will be measured in either teaspoons or tablespoons for the customer.

So it's important to understand that when preparing and dispensing medications.

With a little practice, these conversions will become automatic. Just remember to be careful and never add a decimal place at the end of a whole number.

2 ounces for example, will never be written as 2.0 ounces. Decimal places and periods are the most common causes of mistakes in pharmacies.

So remember to take the extra time to double check every conversion you make and explain everything in simple and easy to understand language for the customer.

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