1. Lesson 1: English System
Measurement Systems
Lesson 1: English System

2. Lesson 1– Measurement Systems
Various systems of measurement are used in health care:
English
Metric
Apothecary
Each system has its own units of measurement to designate length, volume, and weight.
Measurement Systems
Various systems of measurement are used in health care. These systems include the English system, the metric system, and the apothecary system. Each system has its own units of measurement to designate length, volume, and weight. Health care workers must learn how to use each system, as well as how to convert measurements from one system to another.

3. Lesson 1– The English System
The English system is the most common measurement system in the United States.
It is sometimes called the household system.
The English system is not the most accurate measurement system.
The English System
The English system is the most common measurement system in the United States. It is sometimes called the household system. The English system is not the most accurate measurement system. However, health care workers must learn to express measurements using this system so that patients, especially those in the United States, will understand information about their health care.

4. Lesson 1– English System: Length
Inch (in)
Foot (ft)
Yard (yd)
Mile (mi)
English System: Length
In health care, units of length are used to measure a patient’s height. For adults and children, height is usually taken by using the measuring bar on a balance beam scale. For infants, height is determined by the measurement markings made on a flat surface. Length units are also used to measure the circumference of an infant’s head.
In the English system, length is measured in the following units:
inch (in)
foot (ft)
yard (yd)
mile (mi)

5. Lesson 1– English System: Weight
Ounce (oz)
Pound (lb)
Ton (tn)
English System: Weight
In health care, a patient’s weight is usually measured on a balance beam scale. In the English system, weight is measured in the following units:
ounce (oz)
pound (lb)
ton (tn)

6. Lesson 1– English System: Volume
Drop (gtt or gt)
Teaspoon (t or tsp)
Tablespoon (T or tbsp)
Ounce (oz)
Cup (c)
Pint (pt)
Quart (qt)
Gallon (gal)
English System: Volume
In health care, units of volume, or capacity, are used when prescribing medication to be taken at home. Cleaning solutions and beverages may also be measured using English units. In the English system, volume is measured in the following units:
drop (gtt or gt)
teaspoon (t or tsp)
tablespoon (T or tbsp)
ounce (oz)
cup (c)
pint (pt)
quart (qt)
gallon (gal)

7. Lesson 1– Convert English Units
The units in the English measuring system are related to each other.
Simple calculations may be used to convert from one unit to another.
Health care workers should memorize these relationships.
Convert English Units
The units in the English measuring system are related to each other. This chart shows the relationships between units. Simple calculations may be used to convert from one unit to another. Health care workers must memorize these relationships.

8. Lesson 1– Convert English Units: Example 1
How many cups is 64 ounces of water?
Determine the number of ounces in 1 cup.
Divide the total number of ounces by the number of ounces in 1 cup.
Identify the answer.
Convert English Units: Example 1
The units in the English measuring system are related to each other. This chart shows the relationships between units. Simple calculations may be used to convert from one unit to another. Health care workers must memorize these relationships.
Example: It is generally recommended that adults drink 64 ounces of water each day. How many cups is this? Follow these steps to convert ounces to cups:
Determine the number of ounces in 1 cup: 1 cup = 8 ounces
Divide the total number of ounces by the number of ounces in 1 cup: 64 ÷ 8 = 8
Identify the answer: Adults should drink 8 cups of water per day.

9. Lesson 1– Convert English Units: Example 2
How many ounces is 7 pounds?
Determine the number of ounces in 1 pound.
Multiply the total number of pounds by the number of ounces in 1 pound.
Identify the answer.
Convert English Units: Example 2
In the previous example, a smaller unit (ounces) was converted to a larger unit (cups). When converting from smaller to larger, division is used. However, multiplication must be used to convert a larger unit to a smaller unit.
Example: An infant weighs 7 pounds. How many ounces in this? Follow these steps to convert pounds (a larger unit) to ounces (a smaller unit):
Determine the number of ounces in 1 pound: 1 pound = 16 ounces
Multiply the total number of pounds by the number of ounces in 1 pound: 7 × 16 = 112
Identify the answer: The infant weighs 112 ounces.

10. Lesson 1– Convert English Units: Example 3
How many inches and feet is 54 inches?
Determine the number of inches in 1 foot.
Divide the total number of inches by the number of inches in 1 foot.
Multiply the number of whole feet by the number of inches in 1 foot.
Subtract the product of #3 from the total number of inches.
Identify the answer.
Convert English Units: Example 3
Conversions within measuring systems do not always work out evenly. For example, when converting from inches to feet, it is likely that there will be several inches remaining after the whole number of feet is determined. Special care must be taken to label the units of measurement correctly.
Example: A medical assistant measures the height of a patient as 54 inches. How many feet and inches is this? Follow these steps to convert inches to feet and inches:
Determine the number of inches in 1 foot: 1 foot = 12 inches
Divide the total number of inches by the number of inches in 1 foot: 54 ÷ 12 = 4.5. Notice that 4.5 does not equal 4 feet and 5 inches. The figure 4.5 means 4 and 5 tenths, or 4 and 1/2 feet.
Multiply the number of whole feet by the number of inches in 1 foot: 4 × 12 = 48
Subtract the product of #3 from the total number of inches: 54 – 48 = 6. Notice that 6 is the number of inches that remain after the whole feet are subtracted from the patient’s height.
Identify the answer: The patient is 4 feet and 6 inches tall.