How to Do Unit Conversions
Converting units of measurement is an essential part of working with world measurement systems. Let’s learn the basics of unit conversions!
Author
Katie Wickliff
Published:
Oct 2024
Key takeaways
- • The two main measurement systems are metric and customary. Most of the world uses the metric system, but the United States uses the customary system.
- • To convert from a larger unit to a smaller unit, multiply.
- • To convert from a smaller unit to a larger unit, divide.
Whether you’re checking the weather, determining how long it will take to get to soccer practice, or seeing how tall your child has grown in the past year, measurement is everywhere.
Often, you’ll need to convert units of measurement from one form to another. For instance, a recipe might call for 16 fluid ounces of liquid, and if you only have measuring cups, a unit conversion tells you that 16 ounces is the same as two cups.
In this article, we’ll cover the basic measurement conversion rules and explain how to convert units of length measurement, weight measurement, and volume measurement in both customary and metric systems
Table of contents
What are Unit Conversions?
First, let’s define the term “unit” as it relates to measurement. A unit of measurement is a system that describes the size of something. Unit conversions take the measurement of something in one set of units and change it to an equal measurement in another set of units.
Why are Unit Conversions Important?
Converting between measurement units is important when working within and between measurement systems. There are two systems of measurement used worldwide: the metric system and the imperial (or customary) system. Most of the world uses the metric system, but a few countries, including the United States, use the customary system.
The conversion of units is important because it enables us to use different systems and scales to share measurements, which allows for collaboration with other countries.
Unit conversion is also important to calculate and compare measurements between systems. For example, a runner who normally measures their training runs by miles will need to understand the unit conversion of miles to kilometers if they sign up for the popular “5K” race distance.
Even within the United States, industries have varying needs and preferences when it comes to measurement systems. For example, the customary system is often used for consumer products and industrial manufacturing, while the metric system is most often used in fields like science and medicine.
How to Convert Units of Measurement
When your student is first learning unit conversions, it helps to have a few basic guidelines.
Rule 1: When converting from a larger unit to a smaller unit, multiply.
Example: If you are 5 feet tall and you want to know your height in inches, multiply:
5×12=60 inches
Rule 2: When converting from a smaller unit to a larger unit, divide.
Example: If your older brother is 72 inches tall, and you want to know how many feet tall he is, divide:
72/12= 6 feet
This basic rule applies to all conversions, no matter the object being measured or the system you’re using.
Unit Conversion Tables
Length
Metric System
1 kilometer = 1,000 meters
1 meter = 100 centimeters
1 meter =1,000 millimeters
1 centimeter = 10 millimeters
Customary System
1 mile = 5,280 feet
1 mile = 1,760 yards
1 yard = 3 feet
1 foot = 12 inches
Weight
Metric System
1 kilogram = 1,000 grams
1 gram = 1,000 milligrams
Customary System
1 ton = 2,000 pounds
1 pound = 16 ounces
Volume
Metric System
1 liter = 1,000 milliliters
Customary System
1 gallon = 4 quarts
1 quart = 2 pints
1 pint = 2 cups
1 cup = 8 fluid ounces
Practice Problems
Click on the boxes below to see the answers!
Answer:
D
4×12= 48 inches
150 millimeters.
15×10=150 millimeters
He would need to drink 4 full water bottles to achieve his goal. There are 4 quarts in 1 gallon, so:
4×1=4 quarts
Piper does not have enough ribbon to make a wreath. There are 3 feet in 1 yard, so:
3×3= 9 feet
The runner covers 10 kilometers during her run. 10,000/1,000= 10 kilometers
FAQs about the conversion of units
KHDDCM stands for “King Henry Died Drinking Chocolate Milk,” which is an acronym to help students remember measurement increments in the metric system.
King Henry Died Drinking Chocolate Milk is a mnemonic device that helps students remember metric measurement increments: Kilo, Hecto, Deca, Unit, Deci, Centi, Milli.
