Shoppers are voicing their frustration following a change that caused items being listed as the wrong size.
The popular resale platform has updated its size classifications for women's and children's garments failing to inform all users about the change.
Countless users and merchants have taken to social media stating that platform listings now display a modified sizing category than originally posted because of the remapping.
The company said the revised method more closely matches comparable marketplaces.
The platform has recommended to check their listings and manually change the size where appropriate, resulting in member annoyance.
Previously, the measurements included a single numeric size and a letter, for instance S/8 or M/10.
The new system has an alphabetical indicator and numerical range such as S/UK 8-10.
For certain items, the size labels have been reassigned - for example a size L used to be a 12 but is now a UK 16-18.
One content creator, who creates plus-size fashion videos, said the change "makes both selling and buying harder".
"Not many brands say XL is a 20-22," as the platform currently indicates.
A different member, located in Scotland, stated items she posted on Vinted with size 14 labels were displaying on the service as size 20–22.
"If buyers measuring 20-22 acquire them they're going to be very disappointed," she explained.
Another shopper, located in England, said she had been left angered because the modification necessitated personal updates the sizes on "every single listing".
"Personally, this is quite irritating, as I'm chronically ill and selling on Vinted has been paramount for me since losing part of my income," she explained.
The service features exceeding 100 million members, including 18 million in the UK.
It has proved a popular alternative compared to resale services such as eBay and Depop.
This represents another occasion that an unexpected update on the platform has faced criticism: previously, Vinted reversed a change concerning shipment methods after backlash from users.
Liam Verhoeven is a digital content curator who scours the web for the most engaging reels and videos.