Metric Measurement: King Henry

Contributor: Meghan Vestal. Lesson ID: 11340

Who is King Henry? Was he the "liter" of a country? Did he have a "gram" and grandpa? "King Henry" is a way to remember the different units of metric measurement. Conversion is easy, using decimals!



learning style
Kinesthetic, Visual
personality style
Lion, Beaver
Grade Level
Intermediate (3-5)
Lesson Type
Dig Deeper

Lesson Plan - Get It!


King Henry died unexpectedly drinking chocolate milk.

What does this wacky saying have to do with the metric system?

You should recall that throughout this Metric Measurement series of Related Lessons, found in the right-hand sidebar, it has been mentioned that the metric system revolves around decimals.

It has also been mentioned that all units of measurement (length, weight, and volume) have a root word, and you change out the prefix at the beginning of the word to describe different measurements. The prefixes that are used include:

  • kilo-
  • hecto-
  • deka-
  • deci-
  • centi-
  • milli-

By lining up these prefixes in a chart, you can easily figure out how many centimeters are in a kilometer, and how many milliliters are in a liter. This is where King Henry comes in!

By remembering the mnemonic device (saying) used to help you memorize and retain information, "King Henry Died Unexpectedly Drinking Chocolate Milk," you can remember how to set up your chart. Each word in the King Henry phrase represents a metric unit:

King kilo-
Henry hecto-
Died deka-
Unexpectedly unit
Drinking deci-
Chocolate centi-
Milk milli-


When you look at the chart, is there one unit that doesn't look like the others? If you see it, tell your teacher or parent.

"Unit" on the chart looks a little different from the other terms. This is because "unit" does not represent a prefix. Unit stands for the base unit being used (meters, grams, or liters).

The King Henry phrase also helps you remember one other important piece of information. The order helps you remember the value of each unit.

A kilo- always represents the largest metric unit, and a milli- always represents the smallest metric unit. Think about what you have learned about metric units of length. Which unit is the largest? Which unit is the smallest? Tell your teacher or parent.

A kilometer is the largest metric unit of length and a millimeter is the smallest metric unit of length. To learn more about the value of each unit, watch Understanding the Metric System by Smith Math Academy (below):


After the video, discuss the following questions with a teacher or parent:

  • What are the three base units in the metric system?
  • What is the value of one dekameter?
  • What is the value of one milliliter?
  • What is the value of one decigram?

As you saw in the video, the metric system is based on sets of 10. You move up or down the prefix scale by adding a zero or taking away a zero, and by moving the decimal.

Now, let's practice setting up the chart so you can use it to help you move your decimals. Copy the following chart onto a separate piece of paper. You will notice that each letter on the chart represents a letter from the King Henry phrase, or a metric unit:

metric chart


Now, watch the video below to practice moving the decimal to make metric conversions. Use the chart you copied on your paper to follow along with the examples shown in the video. [NOTE: Base and unit refer to the same location on the chart.]

Converting Metric Units using King Henry by SmithMathAcademy:


Once you get the hang of metric conversions, they are fun and easy.

Move on to the Got It? section to practice using your chart to make metric conversions.

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