Members of the platform have expressed outrage due to a modification that led to items being listed as the wrong size.
The second-hand shopping app has revised its measurement guidelines for women's and children's clothes without notifying all users about the change.
Numerous buyers and vendors have taken to social media stating that platform listings now display a modified sizing category compared to what was initially listed due to the recalibration.
The company said the revised method more closely matches other platforms.
It has advised users to review their products and adjust the sizing manually where appropriate, causing user dissatisfaction.
Before the change, the sizing featured numerical and alphabetical indicators, such as S/8 or M/10.
The updated approach includes a letter and a range for example S/UK 8-10.
For certain items, the measurements have been reclassified - for example a size L was formerly size 12 but now shows as UK 16-18.
One content creator, who makes TikTok content about plus-size fashion, stated the update "complicates both purchasing and selling".
"Rarely do manufacturers list XL as sizes 20-22," the way the service now categorizes.
Stephanie Gallen, located in Scotland, explained products she uploaded on Vinted with size 14 labels were appearing on the platform as larger sizing 20-22.
"Should someone sized 20-22 purchase these they may become frustrated," she said.
A different user, located in England, said she had been left angered by the change as she had to manually change the measurements for "each individual item".
"This situation is especially annoying, since I have chronic health issues 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 is not the initial instance where an unanticipated change on the platform has faced criticism: last year, Vinted reversed a change regarding delivery choices following member complaints.