Shoppers are voicing their frustration due to a modification that led to listings displaying inaccurate size information.
This online marketplace has altered its sizing categories for female and kids' apparel but did not contact all shoppers about the modification.
Many shoppers and sellers are posting online saying Vinted listings now show a different size category compared to what was initially listed because of the remapping.
The company said the revised method more closely matches comparable marketplaces.
They have suggested members to examine their items and manually change the size when needed, which has left users frustrated.
Previously, the measurements included one number and one letter, for instance S/8 or M/10.
The updated approach includes a letter with a size spectrum like S/UK 8-10.
For certain items, the measurements have been reclassified - like an L measurement was previously a 12 but currently displays as UK 16-18.
Frankie Bridger, who produces content about larger sizing, said the change "makes both selling and buying harder".
"Not many brands say XL is a 20-22," the way the service now categorizes.
Another user, based in Glasgow, stated items she posted featuring size 14 markings were appearing on the platform as measurements 20-22.
"If buyers measuring 20-22 acquire them they're going to be very disappointed," she explained.
Charlotte Lunn, from Derby, explained she became annoyed because the modification necessitated personal updates the sizes on "every single listing".
"Personally, this is quite irritating, since I have chronic health issues and selling on Vinted has been paramount following partial earnings loss," she said.
The app has more than 100 million users, with 18 million British users.
It has emerged as a preferred choice to second-hand platforms like eBay and Depop.
This isn't the first time where an unanticipated change within the service has received backlash: previously, Vinted reversed a change concerning shipment methods after backlash from users.
Elena is a tax policy analyst with over a decade of experience in interpreting IRS data and advocating for taxpayer rights.