Vanity sizing: the quick answer and why it matters right now
You pick the same size in two stores and the fit swings from loose to impossible. That jolt has a name: vanity sizing. It means labels show smaller numbers for larger measurements, designed to flatter and nudge a purchase.
The practice reshapes expectations and muddles returns. It has grown in a retail world with no universal sizing law and fierce competition online. Understanding how it works saves time, money, and a bit of confidence.
What vanity sizing is, in plain words
Vanity sizing happens when a brand adjusts the body measurements behind a size label, so a size 8 today fits closer to what a size 10 used to be. The number feels friendly, the try-on feels easier, and the cart fills up faster.
There is no single, mandatory size chart in the US or EU. Brands target their own customer data and build distinct fit blocks. ISO 8559-2 was published in 2017 to harmonize garment size designation, but adoption varies and it does not act like a law (ISO 8559-2:2017).
The ripple effect touches returns, sustainability, even self-perception. It also explains why one brand’s “M” sits nothing like another’s.
Proof it’s real: dates, numbers, and sources
Retailers have documented the shift. “One Size Fits Nobody” in The New York Times detailed how labeled sizes grew roomier while numbers shrank, highlighting the drift across US brands (New York Times, 2011).
A concrete signal hit headlines when J.Crew introduced size “000” in 2014, a move that underscored shrinking labels amid changing fits (The Washington Post, 2014).
Body shapes have moved too. The national SizeUK project measured roughly 11,000 adults with 3D scanners in 2004, offering data that helped brands recalibrate blocks and contributed to size divergence over time (SizeUK, 2004).
And it bites in e-commerce. Narvar reported that size or fit drove 42 percent of returns in its consumer study, a costly feedback loop amplified by inconsistent labels (Narvar, State of Online Returns, 2018).
Common traps and how to shop smarter despite vanity sizing
The problem can be solved at the fitting room and on your phone. Small habits make a big difference, especially when you move between brands or fabrics.
- Know your current body metrics in inches and centimeters: bust, waist, hips, inseam, shoulder.
- Check brand-specific size charts and look for finished garment measurements, not just “S M L”.
- Read fabric content and ease: stretch, weave, and intended silhouette change the fit.
- Scan recent reviews for height, weight, and fit notes from people with similar shapes.
- Prefer retailers that share size tools or 3D fit guidance, and keep your profile updated.
- When in doubt, order two adjacent sizes only if returns are free and fast.
- Re-measure seasonally. Bodies change. Wardrobes should accomodate you, not the other way around.
Why brands do it and what could actually change
Brands chase conversion, loyalty, and fewer cart abandons. A smaller number can feel good and lift the odds of a purchase. Over time, each label tunes its block to its core shopper, which widens the gap between competitors.
Standardization exists on paper. ISO 8559-2 gives a shared language for body measurements and size codes. Industry advisers like Alvanon have pushed data-led blocks so collections align with real populations. Adoption still depends on each company’s strategy and margin pressures.
Digital fit is the near-term bridge. Retailers plug in tools built on vast try-on datasets, which predict the best size for your shape and for that specific garment. True Fit has publicized a Fashion Genome based on data from thousands of brands and millions of shoppers, aiming to cut returns through better recommendations.
That leaves one missing piece: transparency. When brands publish exact garment measurements and consistent ease policies, shoppers pick faster and return less. Pair that with your measurements and a saved fit profile, and vanity sizing loses its sting. It becomes just a label, not a roadblock.
Sources: New York Times, “One Size Fits Nobody: Seeking a Steady 4” (2011) https://www.nytimes.com/2011/01/20/business/20sizing.html ; The Washington Post, “J.Crew defends new size 000” (2014) https://www.washingtonpost.com/news/business/wp/2014/07/10/j-crew-defends-new-size-000/ ; SizeUK national sizing survey (2004) overview https://webarchive.nationalarchives.gov.uk/ukgwa/ukwon/file/ ; ISO 8559-2:2017 standard page https://www.iso.org/standard/65420.html ; Narvar, State of Online Returns (2018) https://www.narvar.com/resources/reports/state-of-online-returns.