Shoppers are voicing their frustration after an update resulted in products showing incorrect sizing.
The second-hand shopping app has updated its measurement guidelines for women's and children's garments without notifying every member regarding the update.
Numerous buyers and vendors are posting online saying Vinted listings now show a modified sizing category compared to what was initially listed as a result of the reclassification.
Vinted explained the new system was more in line with comparable marketplaces.
It has advised users to review their products and adjust the sizing manually where appropriate, causing user dissatisfaction.
Before the change, the measurements included a single numeric size and a letter, for instance S/8 or M/10.
The updated approach includes a letter with a size spectrum for example S/UK 8-10.
For certain items, the size labels have been reassigned - for example a size L was previously a 12 but now shows as UK 16-18.
One content creator, who creates plus-size fashion videos, explained the modification "makes transactions more difficult".
"Few clothing companies classify XL as 20-22," as the platform currently indicates.
Stephanie Gallen, from Glasgow, explained products she uploaded featuring size 14 markings were displaying on the service as larger sizing 20-22.
"If anyone [who is] size 20-22 buys them they may become frustrated," she explained.
Another shopper, located in England, stated she felt frustrated by the change as she had to manually change the sizes on "every single listing".
"Personally, this is quite irritating, because of my ongoing medical condition and Vinted sales have been crucial for me since losing part of my income," she said.
The app has more than 100 million members, comprising 18 million UK members.
It has emerged as a preferred choice compared to resale services such as eBay and Depop.
This isn't the first time when a surprising modification within the service has received backlash: last year, Vinted reversed a change regarding delivery choices following member complaints.
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