Customary units - Definition with Examples

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Customary Units

Customary system

The customary system of measurement is defined as a set of weights and measures used for measuring length, weight, capacity, and temperature. Based on the English system of measurement, it is also known as the U.S. Customary System.


Customary Units for Length

The customary units to measure length and distances in the customary system are inches, feet, yards, and miles.

Customary Units for Measuring Length






We can use the given chart for conversion of one customary unit of length to another. 

Customary Units for Length


Example: Convert 5 foot to inches.

1 foot = 12 inches

5 foot = 12 × 5 = 60 inches


The table given below shows the relation between customary units and standard metric units.

Customary Unit

Customary Equivalent

Standard Metric Equivalent

1 inch


2.54 centimeters

1 foot

12 inches

0.3048 meters

1 yard

3 feet

0.9144 meters

1 mile

1760 yards

1.609 344 kilometers


Customary Units for Weight

The U.S. customary units for measuring weight are ounces, pounds, and tons. 

Customary Units for Measuring Weight




We can convert the customary unit of weight by using the giving relations.

Customary Units for Weight


Example: How many ounces are there in 1 ton?

1 ton = 2000 pounds

1 pound = 16 ounces

So, 2000 pounds = 2000 × 16 = 32000 ounces

Customary Unit

Customary Equivalent

Standard Metric Equivalent

1 ounce


28.349523125 grams

1 pound

16 ounces

453.59237 grams

1 ton

2000 pounds

907.18474 kilograms


Customary Units for Capacity (Volume)

The U.S. customary capacity or volume measurement units are ounces, cups, pints, quarts, and gallons. 

Customary Units for Measuring Capacity (Volume)

Fluid Ounce Cup Pint Quart



Example: Convert 3 quarts to cups.

1 quart = 2 pints

3 quarts = 6 pints


1 pint = 2 cups

6 pints = 6 × 2 = 12 cups

Customary Unit

Customary Equivalent

Standard Metric Equivalent

1 fluid ounce

2 tablespoons

29.5735295625 milliliters

1 cup

8 fluid ounces

236.5882365 milliliters

1 pint

2 cups

473.176473 milliliters

1 quart

2 pints

0.946352946 liters

1 gallon

4 quarts

3.785411784 liters


Customary Units for Temperature

The U.S. customary measurement unit  for temperature is °Fahrenheit.  

1 °C = 33.8 °F


  Fun Facts

  • Customary system is called the International System of Units or the Modern Metric System.


Frequently Asked Questions

  • What are customary units of length?

    In the US customary system, inch, foot, yard, and mile are used for measuring length. 1 foot = 12 inches, 1 yard = 3 feet, and 1 mile = 1,760 yards.

  • How many countries use customary units?

    There are three countries in the world that use customary units – the United States, Myanmar, and Liberia. The majority of countries use metric units and a few countries use a hybrid system.

  • What are some advantages of using metric units instead of customary units?

    In the metric system, units have the same root word & only the prefix changes (e.g., millimeter, centimeter, decimeter, etc.), so they are easier to learn. In the US customary system, units do not sound alike (e.g., inch, foot, yard).

  • Are imperial and customary systems the same?

    Imperial and customary systems are not exactly the same. Units such as cubic inches, cubic feet, etc. are the same in both systems, however, units like bushels, gallons, etc. are different in the two systems. One set of units is used for fluids and another for dry goods in the US standard system (e.g., US liquid quart and US dry quart). There is only one set of units for both fluids and dry goods in the imperial system.

Practice Problems on Customary units

Pick the correct answer
1.   7 yards equals how many feet?
2.   How many ounces make 4 pounds?
3.   1 gallon equals how many pints?
4.   Convert 10ºC into Fahrenheits.
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