US Apparel Sizing

• In the US, "women’s apparel sizing is arbitrary, non-determinate, and differs among factors such as style, age or size classification, and brand. This lack of uniformity presents challenges when discussing and classifying female populations and individuals by clothing size and not by body measurements."
• ASTM-I is recognized as a leader in the development and delivery of voluntary consensus standards and provides clothing size standards for females, however, standards are driven by the private sector in the US. Labels and clothing sizes are governed by individual apparel companies in the US, with no legal regulation.
• "The National Health and Nutrition Examination Survey (NHANES) and CDC anthropometric data contribute to ASTM-I clothing size suggestions." The American National Standards Institute (ANSI) also coordinates the activities of the standards development community in the US.
• "Many women’s apparel manufacturers base their current size labeling on one of two resources: ASTM-I’s standard tables of body measurements, or the US voluntary size standards, which were published in 1958 and based on data collected in the 1930s."
• Clothing sizes have become even less reliable over the years as the US population has become more diverse in body shape and size.
• "The 2004 publication of the SizeUSA national survey claims to be an excellent database for size comparison, but it is not available to the public."

CDC/ NHANES Body Measurements Data

Women:

• Height in inches: 63.6 
• Weight in pounds: 170.5
• Waist circumference in inches: 38.7 
• Additional data on body measurements can be accessed here.

Additional Insights

• The average American woman wears a size 16 to 18, not size 14, as once was assumed.

• According to Forbes, plus size clothing is based on the dimensions of women between the sizes 0 to 6.
• An estimated 100 million American women are thought to be a size 14 or above.
• One study that measured more than 5,500 women in the United States, revealed that over the last two decades the average waist size has increased by 2.6 inches, from 34.9 inches to 37.5 inches.

Summary

• For this hour, we tried identifying as much of the requested information as possible. We were able to find some early insights on US apparel sizing.
• We found that most women’s apparel manufacturers base their current size labeling on ASTM-I’s standard tables, however, this is not publicly available but can be purchased for a fee. We also found that the SizeUSA 2004 survey is another database used for size comparison, but it is also not available to the public.
• We also found that the National Health and Nutrition Examination Survey (NHANES) and CDC anthropometric data contribute to ASTM-I clothing size suggestions. A link to their most recent data for US body measurements can be accessed here.
• Based on the information, determining good fitting straight jeans and giving an estimate of the number of sizes of straight style jeans which would be required to fit all body types in the United States appears difficult since women’s apparel sizing in the US appears arbitrary.
• In the course of our research, we also came across some information on merchandising classifications in the US clothing industry and insights on what consumers think about clothing fit in the US, which might also be of interest.
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