Customary Units: Introduction
The customary system of measurement, also called the U.S. Customary System, uses customary units. It is based on the English system of measurement. In math, the customary system can be defined as a set of weights and measures used for measuring length, weight, area, capacity and temperature.
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Definition of Customary Units
Customary units (US Customary Units) are the units that are used to measure length, weight, and volume, most commonly in the USA.
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U.S. Customary Units
The customary units are used in the United States.
Some examples of the U.S. Customary Units are foot, ounce, pint, etc.
Customary System
The customary system of measurement, also called the U.S. Customary System (USCS), is based on the English system of measurement. In math, the customary system can be defined as a set of weights and measures used for measuring length, weight, capacity and temperature.
Customary Units of Length
We can use the customary units like inch, foot, yard, and mile to measure length.
- A paperclip is about 1 inch long.
- A measuring ruler is 1 foot long.
- A hockey stick is 1 yard long approx.

Inch: Inch is used to measure the length of small objects. Example: Length of a sharpener.
Foot: Foot is used to measure short height and distances. Example: Height of a chair.
Yard: Yard is used to measure length of longer distance. Example: Length of a basketball field.
The following are some conversions based on the customary units of length.
- 1 foot (ft) $= 12$ inches (in.)
- 1 yard (yd) $= 3$ feet (ft)
- 1 mile (mi) $= 5,280$ feet (ft)
Customary Units of Weight
We can use the customary units like ounce, pound, and ton to measure weight.
- A pencil weighs about 1 ounce.
- A loaf of bread is about 1 pound.
- An African elephant weighs about 1 ton.

Alt tag: customary units of weight
Ounce: Ounce is used to measure the weight of small objects. Example: weight of a tomato.
Pound: Pound is used to measure weight of a body or furniture. Example: weight of a chair.
Ton: Ton is used to measure the weight of large, heavier things. Example: weight of a truck.
Following are some conversions based on the customary units of weight.
- 1 pound (lb.) $= 16$ ounces (oz.)
- 1 ton $= 2,000$ lbs.
Customary Units of Capacity
We can use the customary units like fluid ounce, cup, pint, quart, and gallon to measure capacity.
- Two bottles of ink hold about 1 fluid ounce.
- A teacup has a capacity of 1 cup.
- A large glass has a capacity of 1 pint.
- A packet of liquid cleanser contains about 1 quart.
- A jug of water contains 1 gallon.
Fluid Ounce: Fluid ounce is used to measure the capacity of a liquid in very less quantities. For example: Fluid ounce of milk.
Cup: Cup is used to measure the capacity of a liquid in less quantities. For example: A cup of tea.
Pint: Pint is used to measure the capacity of a liquid in medium quantities. For example: A pint of cold drink.
Quart: Quart is used to measure a little large capacity of liquid. For example: A quart of liquid detergent.
Gallon: Gallon is used to measure large capacity of liquid. For example: A gallon of water.
You can convert between these units. Use the table to see how.
- 1 cup (c.) $= 8$ fluid ounces (fl. oz.)
- 1 pint (pt.) $= 2$ c.
- 1 quart (qt.) $= 2$ pt.
- 1 gallon (gal.) $= 4$ qt.
Customary Units of Area
The US customary units of Area include square inches, square feet, and square yards.
$1 \text{ft}^2 = 144 \text{in}^2$
$1 \text{yd}^2 = 9 text{ft}^2$
We use acres and $mi2$ for measuring large areas.
1 acre $= 43,560 \text{ft}^2$
$1 \text{mi}^2 = 640$ acres
Customary Units of Volume
In the US customary system these include $\text{in}^3, \text{ft}^3$, and $\text{yd}^3$.
$1 \text{ft}^3 = 1,728 \text{in}^3$
$1 \text{yd}^3 = 27 \text{ft}^3$
Customary Units of Temperature
We use the Fahrenheit $(°\text{F})$ scale for measuring temperature in the US customary system. Two reference points are:
$32 °\text{F}$ : The freezing point of water
$212 °\text{F}$ : The boiling point of water
Metric System vs. Customary System
The international system of units (S.I. system), also known as the metric system, is used across most countries in the world other than in the United States. The United States follows the Customary units of measurement, which uses feet, quarts, and ounces for measurement.
In the metric system, the base units are meter, liter, and gram.
Let’s understand some important formulas for converting metric units of length to customary units.
- 1 meter $= 39.4$ inches $= 1.09$ yards $= 3.2$ feet
- 1 centimeter $= 0.39$ inches
- 1 inch $= 2.54$ cm
Length and distances in the customary system are measured in inches, feet, yards and miles.
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 |
The U.S. customary weight measurement units are ounces, pounds, and tons.
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 |
The U.S customary capacity or volume measurement units are ounces, cups, pints, quarts, and gallons.
Customary Unit | Customary Equivalent | Standard Metric Equivalent |
1 fluid ounce | 2 tablespoons | 29.5735295625 milliliters |
1 cup | 8 fluid ounces | 0236.5882365 milliliters |
1 pint | 2 cups | 473.176473 milliliters |
1 quart | 2 pins | 0.946352946 liters |
1 gallon | 4 quarts | 3.785411784 liters |
The U.S customary temperature measurement unit is degree Fahrenheit. 1 Degree Celsius = 33.8 Degree Fahrenheit
Let’s do it!
Instead of handing our word problem worksheets to your child, site real life instances in which the child is required to measure length, weight or capacity and convert bigger customary units into smaller units or convert metric units into customary units and vice versa.
Solved Examples
1. How many inches are in 1 yard?
Solution:
1 yard (yd) $= 3$ feet (ft)
1 feet (ft) $= 12$ inches
1 yard $= 3 \times 12$ inches $= 36$ inches
2. How many cubic inches are in 1 cubic yard?
Solution:
1 yard $= 36$ inches
1 cubic yard $= 36 \times 36 \times 36 = 46,656$ cubic inches
3. How many fluid ounces are in 2 pints?
Solution:
1 cup (c.) $= 8$ fluid ounces (fl. oz.)
1 pint (pt.) $= 2$ c.
1 pint (pt.) $= 2 \times 8 = 16$ fluid ounces (fl. oz.)2 pints $= 2 \times 16 = 32$ fluid ounces (fl. oz.)
Practice Problems
Customary Units
How many pints are equal to 1 gallon?
1 gallon (gal.) $= 4$ qt.
1 quart (qt.) $= 2$ pt.
1 gallon $= 4 \times 2 = 8 pt
How many pounds make 4 ounces?
1 pound (lb.) $= 16$ ounces (oz.)
1 ounce $= \frac{1}{16}$ pound
4 ounces $= 4 \times \frac{1}{16} = \frac{1}{4}$ ounces $=$ One - fourth ounce
8 yards equals how many feet?
1 yard (yd) $= 3$ feet (ft)
8 yards $= 8 \times 3 = 24$ feet
How many ounces make 1 ton?
1 pound (lb.) $= 16$ ounces (oz.)
1 ton $= 2000$ lb.
1 ton $= 16 \times 2,000 = 32,000$ oz.
Which of the following is the correct unit to measure the radius of a coin?
Inch is used to measure the length of small objects.
Frequently Asked Questions
Which countries use customary units?
Three countries in the world use customary units: the United States, Myanmar, and Liberia.
What is the advantage of using metric units instead of customary units?
In the metric system, there is the same root word in units and only the prefix changes (for example: millimeter, centimeter, decimeter, etc.). So, it becomes easier to learn. In the US customary system, units do not have the same root word. (for example: inch, foot, yard). The customary units are a bit complex because you must know the conversion rates.
Are imperial and customary systems the same?
There is a slight difference between the imperial and customary systems.. Units like cubic inches, cubic feet, etc., are the same in both systems, but units such as bushels, gallons, etc., are different in each.
Do scientists use customary units?
No, scientists do not use the customary units. They use the metric system all over the world.
What are SI units?
The International System Of Units (SI) is the metric system accepted universally as a standard for measurements. The International System of Units (SI), is commonly known as the metric system (or the modern metric system).
What is the avoirdupois system?
The avoirdupois system uses pounds and ounces as base units of measurement. It is based on the fact that sixteen ounces makes one pound.