Vinted users have been reacting angrily after an update resulted in items being listed as the wrong size.

The second-hand shopping app has revised its sizing categories for women’s and children’s clothes but did not contact all users about the change.

Many shoppers and sellers have taken to social media saying Vinted listings now show a different size category than originally posted because of the remapping, with one TikTok user describing the conversion as a “nightmare”.

The company said in a post on its website that the new system was more in line with other platforms.

It has advised users to check their listings and manually change the size if necessary, which has left users frustrated.

Hannah-Abby, from Devon, told BBC News she was forced to switch her account to holiday mode, which suspends sales, because she did not have time to update all her listings.

“I think the whole thing just wasn’t clearly thought through,” she said.

“Most of my friends have also put their pages on holiday mode.”

The 35-year-old said she stopped buying clothes on Vinted recently, and is unlikely to return to the platform unless the sizing categorisation reverts to the original system.

She said it was “really frustrating” that she could not physically speak to a person at the company, which she described as being unacceptable.

Vinted said it was changing the sizing system to make shopping on the app “easier than ever”.

Vinted said the update applies only to UK members.

The company said: “Now, the sizes you see on these listings will be more accurate, especially for items purchased from other countries or international brands.

Before the change, the sizes had both a single numeric size and a letter, for instance S/8 or M/10.

The new system has a letter and a range such as S/UK 8-10.

In some cases, the sizing has been recategorised – for example a size L used to be a 12 but is now a UK 16-18.

There are also different numeric size ranges, for instance an XXL/16 size has been changed to XXL/UK 24-26.

One X user wrote: “Grouping the sizing like that is just stupid. It’s going to make it twice as hard for buyers to find things in their size.

“Did anyone actually think this through?”

TikTok user Lisa described the update as confusing and time-consuming.

She said sellers with a lot of listings needed to manually edit every item to correct the sizing, which was unnecessary while other improvements suggested by users remain unaddressed.

“This is not a good change. In fact it’s [going to] be an absolute nightmare if you have to go in and change all of your listings that you’ve already got.”

Frankie Bridger, who makes TikTok content about plus-size fashion, said the change “makes both selling and buying harder”.

“Not many brands say XL is a 20-22,” which is what Vinted now does, Frankie said.

“People have been asking Vinted for years to make the sizing separate, [with] one tag for letters and one for numbers.”

A Vinted spokesperson told BBC News: “We’ve updated our size guidelines for women’s and kids’ clothing to make sizing more accurate across international brands.

“UK members will have received a message in their Vinted inbox with more details and you can also find full information on our help centre.”

Stephanie Gallen, from Glasgow, said garments she listed on Vinted with size 14 labels were appearing on the platform as size 20–22.

She told BBC News she contacted the firm to clarify whether this was an error but is yet to receive a response.

“If anyone [who is] size 20-22 buys them they’re going to be very disappointed,” she said.

Charlotte Lunn, from Derby, said she had been left angered by the change as she had to manually change the sizes on “every single listing”.

“For me this is particularly frustrating, as I’m chronically ill and selling on Vinted has been paramount for me since losing part of my income,” she said.