Brits could be hundreds of pounds richer as the UK braces for the busiest day of the year for second-hand selling.

Online marketplace Vinted has crowned Sunday, January 4, as the nation’s peak moment for listings – dubbing it ‘Sell-It Sunday’ – after data showed activity can soar to three times the normal daily level.

The first Sunday of January has become a ritual clear-out for households across the country, as wardrobes, drawers and cupboards are raided for gifts that don’t fit, duplicate presents and gadgets that never quite made it out of the box.

And the rewards could be substantial. Vinted’s research suggests there is a small fortune sitting unused in British homes, with 51% of people believing they have more than £400 worth of unwanted items gathering dust.

Around one in six reckon the value of their unused belongings tops £1,000. The platform said the new year marks a natural reset point, when many people reassess what they actually need after the excesses of Christmas.

Fashion remains the biggest money-spinner, with clothing that doesn’t fit or isn’t to taste among the most commonly listed items.

Last year’s most popular categories included women’s toiletries, perfumes, jewellery, nightwear and make-up – all classic festive presents that often end up unused.

Demand is not limited to fashion. Vinted said buyers show strong interest in entertainment and electronics, with books, magazines, CDs and vinyl seeing a surge in searches.

More than 55% of UK consumers said they would consider buying these items second-hand, while small electronic products are increasingly appearing among January listings.

The company said the trend highlights a growing willingness among shoppers to turn to resale platforms for everyday purchases.

Jessie de la Merced, Vinted’s vice-president of corporate affairs, said the January spike has become a nationwide habit.

She said: “Sell-It Sunday isn’t just the moment unwanted gifts get a second life. It’s become a national reset, a day when millions of people turn clutter into cash, explore fresh styles and discover everything from fashion to electronics on Vinted.

“It shows how second-hand shopping continues to grow as a smart, stylish choice for 2026.”

Vinted expects unopened gift sets, unused perfumes, books and clothing still carrying original tags to dominate listings this year.

It has urged users to prepare in advance by checking wardrobes and shelves, allowing them to upload items quickly and capitalise on the surge in buyers.

Accessories and nightwear typically see sharp rises in demand in early January, while electronics and entertainment media are forecast to grow further this year.

Industry analysts say early January is now firmly embedded in the retail calendar as a boom period for second-hand sales, with millions logging on to hunt for bargains – and to turn festive clutter into cold, hard cash.