T-shirt Sizing

You think you’re a Large, but when you buy that designer tee it’s just a smidge too big. But pick up the next label's Large and you might find it's way too tight. Feel like your body shape doesn’t fit most conventional T-shirt sizing charts? You're not alone.

Most of us out in the real world probably don’t give a lot of thought to T-shirt sizing, but fortunately, there are some who do.

We started with the premise that men’s T-shirt sizes can vary wildly—an inconsistency that adds frustration to the process of buying online. So, we developing an algorithm that can recommend T-shirt brands and sizes for a wide range of body types.

To create the algorithm, we began by confirming something we’d long suspected: T-Shirt sizing evolves over time. Through washing 10 different T-shirts 16 times each, they were able to measure the fabric's evolution:

Each time a T-shirt is washed, it shrinks, and each time it is worn, it expands. The expansion in the chest is almost 2x more than the expansion in the length and most of that expansion happens in the first two hours of wear. What surprised us was that over the course of many wash cycles, the chest and waist will drift wider and the length will drift shorter.
After 16 wear-wash cycles, the average T-shirt had shrunk to 95 percent of its original length, while the chest had expanded by 5 percent.

Test data shows that the average t-shirt gets both shorter and wider in the chest after repeated wear-wash cycles.
But for us, the more useful data is in the charts that compare sizing of top brands. We “washed, dried, measured, and weighed” 800 of the most popular men’s tees available online. The shirts included a wide variety of price points ($5-$50), sizes, and fits (slim, relaxed, etc.).

The results are fascinating. An XL Zara Relax Fit tee, for instance, comes in at a svelte 20.6 inches in the chest, while a small L.L. Bean Unshrinkable Traditional Fit measures a nearly identical 20.5 inches. Lengths varied even more. A size-S Abercrombie Classic Fit Crew measured a generous 28.2 inches long, while all of Ralph Lauren's XL tees came in at just 27.3 inches.

The testing debunked some common clothing misconceptions, too. For instance, testing revealed that cheaper T-shirts don't weigh less per square yard than their pricier rivals. Instead, it's the other way around. The problem is manufacturing variance Another myth busted: Washing clothes in hot water doesn't cause notable shrinkage.

“While hot water may cause shrinkage in wool garments, for cotton and polyester t-shirts, the washer settings don't make a big difference. The biggest determinant of shrinkage is whether the shirt went in the dryer or not.” The site says it has “binders full of women” requesting a female T-shirt data, and we think sizing info for jeans would be oh-so-helpful for those who hate trying on clothes in a department store.


I can confirm that cold water can cause shrinkage. But all men know that.

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