Vanity sizing, or size inflation, is the phenomenon of ready-to-wear clothing of the same nominal size becoming bigger in physical size over time.^[1][2][3] This has been documented primarily in the United States and the United Kingdom.^[4] The use of US standard clothing sizes by manufacturers as the official guidelines for clothing sizes was abandoned in 1983.^[5][6] In the United States, although clothing size standards exist (i.e., ASTM), most companies do not use them any longer.^[2]

Size inconsistency has existed since at least 1937. In Sears' 1937 catalog, a size 14 dress had a bust size of 32 inches (81 cm). In 1967, the same bust size was a size 8. In 2011, it was a size 0.^[7] Some argue that vanity sizing is designed to satisfy wearers' wishes to appear thin and feel better about themselves.^[2][3] This works by adhering to the theory of compensatory self-enhancement, as vanity sizing promotes a more positive self-image of one upon seeing a smaller label.^[5]

In the 2000s, American designer Nicole Miller introduced size 0 because of its strong California presence and to satisfy the request of many Asian American customers in that state. Her brand introduced subzero sizes for naturally petite women.^[2] However, the increasing size of clothing with the same nominal size caused Nicole Miller to introduce size 0, 00, or subzero sizes.^[2]

The UK's Chief Medical Officer has suggested that vanity sizing has contributed to the normalisation of obesity in society.^[8]

In 2003, a study that measured over 1,000 pairs of women's pants found that pants from more expensive brands tended to be smaller than those from cheaper brands with the same nominal size.^[9]

Although more common in women's apparel, vanity sizing occurs in men's clothing as well. For example, men's pants are traditionally marked with two numbers, "waist" (waist circumference) and "inseam" (distance from the crotch to the hem of the pant). While the nominal inseam is fairly accurate, the nominal waist may be quite a bit smaller than the actual waist, in US sizes. In 2010, Abram Sauer of Esquire measured several pairs of dress pants with a nominal waist size of 36 in (91 cm) at different US retailers and found that actual measurements ranged from 37 to 41 in (94 to 104 cm).^[15] The phenomenon has also been noticed in the United Kingdom, where a 2011 study found misleading labels on more than half of checked items of clothing. In that study, the worst offenders understated waist circumferences by 1.5 to 2 inches (3.8 to 5.1 cm). London-based market analyst Mintel say that the number of men reporting varying waistlines from store to store doubled between 2005 and 2011.^[16]

Vanity sizing is a common fashion industry practice used today that often involves labeling clothes with smaller sizes than their actual measurements size. Experts believe that this practice targets consumer's preferences and perceptions. Although it may seem like a marketing tactic to boost sales, it potentially has an impact that affects consumers' psychological well-being, purchasing behavior tendencies, and self-image perceptions.

Research studies show that vanity sizing is a key factor in a consumer's ideal body image and self-esteem. The study claims that smaller-size labels can promote more positive mental imagery about one's self-image, viewing oneself as thinner and more attractive. One example that the article provides is a hypothetical situation when presented with two t-shirts that look the same, with the only difference being the size, one labeled medium and one labeled a size large. The article explains that consumers would be more willing to pick the t-shirt labeled medium because it makes them feel better about their figure. "'Consumers' decisions are influenced by framing; that is, the way that the good is presented to the consumers.'"^{[17][page needed]} However, this may depend on an individual's self-esteem about their appearance; those with lower self-esteem prefer small labels more. In another article, five studies were conducted, and all concluded that larger clothing sizes had a more negative response from consumers.^{[18][page needed]}

Nevertheless, it is also important to consider the impact of vanity sizing on the plus-size women community. Finding clothes that fit and match personal style is challenging for this group of women. In an academic paper that analyzes the marketing for the plus-size community, the author mentions that "For most retailers plus size consumers are not their main target market unless they exclusively sell plus size clothes. But for the most part plus size consumers do fit into some kind of target market on every other attribute except for sizing."^{[19][page needed]} This can be frustrating for this community, making this group feel excluded and showing the ethical issues of not being able to provide a market for different communities. In addition, In another article that focuses on the plus-size community's satisfaction with retail clothing, the author states, "Additionally, 62% of plus-size women experience difficulty finding desirable clothing styles, and 56% report that it is challenging to find good quality plus-size clothing."^{[20][page needed]} It is crucial embracing diversity in clothing sizing and promoting inclusivity to address issues that maintain sizing discrimination.

Not only does vanity sizing play a part in how consumers view themselves, but it can also be a factor in shaping a consumer's purchasing habits. Oftentimes, consumers lean toward clothing labels with smaller sizes based on how those clothes complement their figure. Retailers may incorporate vanity sizing practices, which can sometimes result in particular consumers having more appeal towards smaller sizes. Another study tests whether perceived deception is connected between a consumer's cynicism and a consumer's outcomes. The article discusses how wearing vanity sizes boosts consumers' self-esteem and adds value to the product that would not have been in those labeled in the actual size.^{[21][page needed]} Larger clothing sizes may influence consumers to purchase more clothing items to improve their self-esteem. However, there are times when people buy clothes, they might choose bigger sizes to feel better about themselves. The flip side of vanity sizing was concluded from their study, which showed that this only sometimes stops people from buying clothes. It can make people want to spend more money overall because they want to feel better about themselves, and buying clothes can help.^[18] This vanity sizing concept suggests that perhaps there is a connection between shopping habits and one's ideal body figure.

While vanity sizing may seem a good advantage for store retailers, it can also change customers' trust if they feel deceived. Customers may lose trust in retailers if they feel they have been deceived by vanity sizing, which could alter their perspectives of a brand. An article analyzing the psychological process of vanity sizes says that retailers must be truthful about the labeled information because this information is essential for consumers. If not sized accurately, it can lead to negative views toward retailers. This can result in future references being affected when using sizing information.^{[21][page needed]} Later in the article, it says retailers should be truthful about the sizing information if they want to sustain more positive customer relationships.^{[21][page needed]} Negative effects, such as dissatisfaction with a purchase or less trust, may result from practices that retailers participate in when sizing labels.

Moreover, retailers must be transparent in sizing practices to address consumers' distrust and perceived deception. Consumers may appreciate it when retailers are more transparent in sizing practices; this can build trust and avoid deceiving perceptions. Vanity sizing often affects women's clothing brands, especially for moderately priced designer brands targeting younger adult female consumers. An article tests the idea that women's apparel sizes would vary depending on their price. The study found that moderately expensive apparel for women tends to be larger than discount brands, while designer brands are more expensive and tend to be smaller than non-designer brands.^{[17][page needed]} In contrast, however, the study also found that children's and men's apparel brands show no vanity sizing practicing on clothes. The fashion industry's sizing standards may reflect gender disparities or pose challenges when conforming to marketing strategies or ideal societal body image.^{[17][page needed]}

• Body image
• The Association for Women with Large Feet
• EN 13402, emerging European and international clothing standard from 2007, based on body measurements in centimeters
• US standard clothing size, an inch based standard based on body measurements, gained little traction and was replaced by vanity sizing from the 1980s
• Inclusive sizing

• Bickle, Marianne C.; Burnsed, Katherine Annette; Edwards, Karen Lear (2017). "Are U.S. Plus-Size Women Satisfied with Retail Clothing Store Environments?". Journal of Consumer Satisfaction, Dissatisfaction & Complaining Behavior. 28: 23–38.
• Franz, Wan-ju Iris (2017). "Economics of Vanity Sizing". Journal of Economic Behavior & Organization. 134: 336–355. doi:10.1016/j.jebo.2017.01.004.
• Hoegg, JoAndrea; Scott, Maura L.; Morales, Andrea C.; Dahl, Darren W. (2014). "The flip side of vanity sizing: How consumers respond to and compensate for larger than expected clothing sizes". Journal of Consumer Psychology. 24 (1): 70–78. doi:10.1016/j.jcps.2013.07.003.
• Ketron, Seth (2016). "Consumer cynicism and perceived deception in vanity sizing: The moderating role of retailer (dis)honesty". Journal of Retailing and Consumer Services. 33: 33–42. doi:10.1016/j.jretconser.2016.07.018.
• Worman, Katelyn (2021). Why Do Retail Stores Sell Plus Size Clothes, but They Do Not Market to the Plus Size Community? (Thesis). Long Beach: California State University.

• Aydinoğlu, Nilüfer Z.; Krishna, Aradhna (2012). "Imagining thin: Why vanity sizing works". Journal of Consumer Psychology. 22 (4): 565–572. doi:10.1016/j.jcps.2011.12.001. hdl:2027.42/142000.
• Rickey, M. (2007-09-22). "Vanity sizing". The Times. London.

• "Study questions the sizing methods in women's apparel". Web2.unt.edu. 16 December 2003. Archived from the original on 2007-03-25. Retrieved 2013-03-14. Press release.