Virtual try-on for secondhand clothing: why fit matters more in resale

New retail has spent years building fit tools: size charts, size recommendation quizzes, generous return windows. Resale grew up without most of that, and it is now big enough that the gap is starting to matter.

How big is the secondhand clothing market right now?

ThredUp's 2026 report puts the global secondhand apparel market at 257 billion dollars in 2025, up 13 percent year over year, on track for 393 billion dollars by 2030. The US portion alone is expected to reach 78.8 billion dollars by 2030. Online resale specifically, the part a shopper reaches through a website rather than a physical thrift store, is projected to nearly double from 29.7 billion dollars in 2025 to 48.3 billion dollars by 2030. Fifty nine percent of US consumers shopped secondhand apparel in 2025, a share that keeps climbing.

That growth is not evenly split. A large share runs through peer to peer marketplaces such as Poshmark, Depop, Vinted, and eBay, where one person lists one item they own. A smaller but growing share runs through curated resale and vintage retailers, businesses that source, grade, and photograph secondhand pieces and sell them through their own storefront the way any other online store does.

Why don't most resale marketplaces accept returns for fit?

Poshmark's policy is direct about it: the platform does not accept returns for buyer's remorse, and fit specifically is named as a reason that does not qualify. A buyer can only open a formal case if an item is not as described, meaning the wrong size or color was listed, undisclosed damage, or the item never arrived. Simply not liking how it fits is not grounds for a return.

New retail can absorb a fit return because the item goes back on the shelf and sells to the next customer. A secondhand item is usually a single unit. Every reship and relist cycle costs the seller time and condition on a piece that cannot simply be reordered from a warehouse, so most resale platforms draw the return line earlier than a typical new retail store would.

Why is fit harder to judge on a one of one resale item?

• There is no second unit to fall back on. A new retailer might stock the same shirt in five sizes. A resale listing is usually the only one of that exact piece, so getting the size wrong once often means the item is gone entirely, not just the wrong size.
• Vintage sizing does not track modern size charts. A garment tagged decades ago can run smaller or larger than the same labeled size today, and the listing rarely explains by how much.
• Wear and washing change the actual measurements. A used garment has often shrunk, stretched, or been altered in ways a new item straight from a factory has not, so even a correct original size tag can be misleading.
• The photo is almost always the only reference. Fit and sizing already drive an estimated half to seventy percent of apparel returns, as covered in our post on fashion ecommerce return statistics, and that is with brand new items that at least have a consistent size chart behind them. Resale has the same core fit problem with fewer of the usual guardrails.

What would a fit preview actually change for a resale buyer?

ThredUp itself has already tried to solve part of this the physical way. Its Goody Box service ships a personalized box of ten to twenty secondhand items to a buyer's home for a flat fee, closer to a try before you buy service than a normal checkout. It works, but it takes days to arrive and costs money up front regardless of whether anything gets kept.

A virtual preview solves the same uncertainty before checkout instead of after it ships. A shopper's own photo and the garment's photo produce a rendered result showing how that exact piece sits on that person, in seconds rather than days, with nothing to return if it does not work out because nothing has been ordered yet.

How does Corlen work for resale and vintage retailers?

Peer to peer marketplaces are not where this fits today. An individual seller listing a dress on Poshmark or Vinted has no product page of their own to add a tool to. Curated resale and vintage retailers running a real storefront are different: on Shopify, Corlen's app adds a try on button directly to the product page, the same as it would for any new garment. Teams building a custom resale storefront can reach the same rendering engine through the developer API.

The render itself works the same regardless of whether the garment is new or secondhand, since it is only reading the garment photo and the shopper's photo, not a size chart or a brand's history. See the full generation process in how virtual try-on works.

See it directly first: try Corlen on your own photo, no account needed for a first result.