Members of the platform have expressed outrage due to a modification that led to items being listed as the wrong size.
The popular resale platform has altered its sizing categories for female and kids' apparel without notifying all users about the change.
Many shoppers and sellers are expressing on platforms saying Vinted listings now show a modified sizing category versus the original listing due to the recalibration.
The platform stated the revised method more closely matches comparable marketplaces.
They have suggested members to check their listings and manually change the size where appropriate, causing user dissatisfaction.
Earlier, the sizes had both numerical and alphabetical indicators, for instance S/8 or M/10.
The revised method features an alphabetical indicator and numerical range like S/UK 8-10.
With some products, the size labels have been reassigned - for example a size L was previously a 12 but now shows as UK 16-18.
Frankie Bridger, who creates plus-size fashion videos, explained the modification "makes transactions more difficult".
"Few clothing companies classify XL as 20-22," the way the service now categorizes.
Stephanie Gallen, from Glasgow, explained products she uploaded featuring size 14 markings were displaying on the service as size 20–22.
"If anyone [who is] size 20-22 buys them they're going to be very disappointed," she stated.
A different user, located in England, said she had been left angered by the change as she had to manually change the sizing for "all her products".
"For me this is particularly frustrating, as I'm chronically ill and platform income has been essential following partial earnings loss," she said.
The platform boasts over 100 million shoppers, comprising 18 million UK members.
It has emerged as a preferred choice to second-hand platforms like eBay and Depop.
This represents another occasion when a surprising modification to the app has proved unpopular: earlier, the service retracted a modification regarding delivery choices after backlash from users.
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