Members of the platform have expressed outrage after an update resulted in listings displaying inaccurate size information.
This online marketplace has altered its sizing categories for female and kids' apparel but did not contact all users about the change.
Countless users and merchants have taken to social media claiming that product pages now present a different size category versus the original listing due to the recalibration.
Vinted explained the new system was more in line with similar services.
The platform has recommended to review their products and manually change the size where appropriate, causing user dissatisfaction.
Earlier, the sizing featured numerical and alphabetical indicators, such as 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 measurements have been reclassified - such as a large size was formerly size 12 but now shows as UK 16-18.
A fashion influencer, who makes TikTok content about plus-size fashion, explained the modification "makes transactions more difficult".
"Few clothing companies classify XL as 20-22," as the platform currently indicates.
Stephanie Gallen, located in Scotland, said garments she listed featuring size 14 markings were showing in the marketplace as measurements 20-22.
"If buyers measuring 20-22 acquire them they will likely be quite upset," she explained.
A different user, from Derby, said she had been left angered due to the update requiring manual adjustment the measurements for "each individual item".
"For me this is particularly frustrating, since I have chronic health issues and Vinted sales have been crucial after experiencing income reduction," she said.
The platform boasts over 100 million users, comprising 18 million UK members.
It has proved a popular alternative compared to resale services such as eBay and Depop.
This isn't the first time when a surprising modification within the service has received backlash: earlier, the service retracted a modification concerning shipment methods due to shopper criticism.
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