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Sizing Up

  • Lesson
Donna Coe
Location: unknown

Students will use measurement to investigate where clothing sizes come from, and to explore how sizes differ between companies and countries.

Most people know what size they wear. And when they grow out of old clothes, they just buy the next larger size. But where do sizes come from? In this lesson, students will use measurement to determine how to choose sizes when ordering from a catalog, and to investigate if clothing sizes are standard throughout the United States and the world.

Read the book Jim and the Beanstalk by Raymond Briggs, a variation of the familiar Jack and the Beanstalk. In this amusing story, Jim helps the giant by measuring him for new glasses, teeth, and hair. After the story, ask, "How many of you know what size clothing you wear?" Allow a brief sharing of information, and then let students know they will be learning about where sizes come from.

In pairs, have students record estimates of their heights, chests, waists, and hips on the My Own Measurements Activity Sheet.

pdficon My Own Measurements Activity Sheet

1933 measure Then, have students use measuring tapes to find the actual measurements. Prior to doing so, however, you may want to discuss how to measure. For instance, lead students to suggest that height is best measured if the person is standing barefoot against a wall. Further, you may need to explain that chest measurements are taken under the armpits, around the highest part of the chest and across the shoulder blades. (Note that older students may be uncomfortable measuring each other. As a modification, this activity can be done using lower grade buddy classes, so that a much younger student is paired with an older student. Another alternative is to omit chest measurements from this activity or substitute a different measurement, such as feet or head.) The image to the right shows that the waist should be measured by placing a tape measure around the midsection so it crosses in front of the belly button.

Students should record their measurements on the activity sheet. Have students compare their estimates to the actual measurements, and then have them compare their actual measurements to a sizing chart. You may also want to have students compare their measurements to charts they find in mail order catalogs or on web sites. Most online retailers have online sizing charts. An interesting discussion may result from comparing sizing charts, as different companies often use different guidelines.

(To avoid interruptions during the lesson, be sure to preview any sites before using them in the classroom.)

Circulate as students are working, assisting and redirecting if necessary. Ask the following questions:

  • What are you finding out about clothing sizes? About your size?
  • What problems are you encountering?

When at least half the class has completed and recorded their measurements, gather the whole group together. Explain that they will have six minutes to work with a different partner to compare their data. (Students will likely do this anyway, so it’s good to schedule time for it during the lesson.) As students discuss, they should look for similarities and differences, and they should share any insights they had during the activity. You may wish to model this by having a discussion about measurements with one student while the whole class listens.

Should students finish before six minutes have passed, they can find a new partner and repeat the task. During student discussions, circulate and take anecdotal notes about which students are interested, on-task, and participating at a high level.

Again convene the whole group. Allow students to share their thoughts, especially around the following questions:

  • What patterns exist in the sizing charts?
  • Who had measurements that fit two or more sizes within a chart? What should that person do if ordering from a company?
  • Do you think these numbers are standard throughout the country? Do you think they are the same from store to store? What about in other countries?
  • Why do you think that some companies number their clothing sizes while others use words like small, medium, and large?

To conclude the lesson, distribute the Clothing Sizes Activity Sheet.

pdficon Clothing Sizes Activity Sheet

Students can work on the activity sheet during class, or they can complete it as homework. Alternatively, you can have students complete one of the activities listed in the Assessment Options section.


Briggs, Raymond. Jim and the Beanstalk. New York, NY: Paper Star Books, 1970.

Assessment Options

  1. As you circulate while students are working, take note of the following:
    • Were students using tape measures accurately?
    • Were the students able to use the data on the charts?
    • Were the students able to identify the correct location on the charts?
  2. During a group discussion, have students share their data and any problems they encountered. Students in the "audience" can use a non-verbal signal (such as the American Sign Language sign for "me, too") to indicate when they had a similar problem. This encourages active listening, provides the teacher with useful information, and reduces repetition of information.
  3. Have students answer the questions on the My Own Measurements and Clothing Sizes Activity Sheets. This can be a written assignment or an informal math conversation.

        Have all students respond to one of the following prompts in writing:

   This lesson was a plus because ____________.

   This lesson was a minus because ____________.

   This lesson was interesting because ____________.


  1. Allow students to estimate and measure to find their sizes for hats, gloves, belts, rings, shoes, and other items. Use the Other Sizes Activity Sheet.
    pdficon Other Sizes Activity Sheet
  2. Find the range, mean, median, and mode of the class for a particular measurement such as hat size or foot length.
  3. Invite a guest speaker from a retail store or tailoring shop to discuss measurement and sizes.
  4. Have students go online to find what their sizes would be in another country. What is the relationship between sizes in the United States and in other countries?
  5. Have students take their measurements again, but this time using metric units. Then, have them find their sizes using charts with metric units. What differences do the students notice in measuring and in finding their sizes on the charts?

Questions for Students 

1. What patterns exist in the sizing charts? Share your findings with the whole group.

[As measurements go up, sizes go up. But it’s not proportional. For instance, girls size increases from 8 to 10 with a 3" increase in height; but from size 12 to 14, it’s only a 2" increase in height.]

2. Who fit the size exactly? Who had measurements that fit two or more sizes? What should those shoppers do? Why?

[Shoppers who have different sizes for different categories should probably use the larger size when placing an order. For instance, if a boy is size 10 by height but size 12 by chest, then he should probably order size 12; if he orders size 10, then the item may fit him for height but it will be tight across the chest.]

3. Do you think these numbers are standard throughout the country? Across different stores? Across different brands of clothing? In other countries? Why do you think that?

[Some other countries probably use metric measurements, so it’s unlikely that sizes are standardized. From store to store, it seems unlikely, too, from personal experience.]

4. Why do you think that some companies number their clothing sizes while others use words like small, medium, and large?

[Answers will vary.]

Teacher Reflection 

  • What were ways the students demonstrated they were actively engaged in the lesson?
  • How did your lesson address various learning styles?
  • How did the students demonstrate understanding of the materials presented?

Learning Objectives

Students will:

  • Measure height, chest, waist, and hip.
  • Compare their measurements to sizing charts found in catalogs.
  • Explain how to choose a size when measurements do not match sizing charts exactly.

NCTM Standards and Expectations

  • Understand that measurements are approximations and how differences in units affect precision.
  • Select and apply appropriate standard units and tools to measure length, area, volume, weight, time,

Common Core State Standards – Mathematics

Grade 3, Measurement & Data

  • CCSS.Math.Content.3.MD.B.4
    Generate measurement data by measuring lengths using rulers marked with halves and fourths of an inch. Show the data by making a line plot, where the horizontal scale is marked off in appropriate units-- whole numbers, halves, or quarters.