Members of the platform have expressed outrage following a change that caused listings displaying inaccurate size information.
This online marketplace has altered its measurement guidelines for women's and children's garments but did not contact every member regarding the update.
Numerous buyers and vendors are expressing on platforms stating that platform listings now display a modified sizing category compared to what was initially listed as a result of the reclassification.
The company said the new system was more in line with other platforms.
It has advised users to examine their items and adjust the sizing manually when needed, causing user dissatisfaction.
Before the change, the sizing featured a single numeric size and a letter, for instance S/8 or M/10.
The updated approach includes a letter with a size spectrum like S/UK 8-10.
In some cases, the size labels have been reassigned - like an L measurement was previously a 12 but is now a 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," as the platform currently indicates.
Another user, located in Scotland, explained products she uploaded with size 14 tags were appearing on the platform as measurements 20-22.
"If buyers measuring 20-22 acquire them they may become frustrated," she stated.
Another shopper, located in England, explained she became annoyed because the modification necessitated personal updates the measurements for "each individual item".
"For me this is particularly frustrating, because of my ongoing medical condition and selling on Vinted has been paramount following partial earnings loss," she explained.
The app has more than 100 million users, including 18 million in the UK.
It has proved a popular alternative compared to resale services such as eBay and Depop.
This isn't the first time where an unanticipated change on the platform has faced criticism: previously, the platform withdrew an update concerning shipment methods after backlash from users.
A tech journalist and digital strategist with over a decade of experience covering emerging technologies and consumer electronics.