Selling privately or commercially?

In short: Whoever only occasionally sells their own things acts privately. Whoever sells regularly, with the intention of making a profit and in a planned way, runs a business and must register it.

In more detail: The overall picture decides: case law examines duration, quantity, share of new goods, purchases for resale, advertising and number of sales. There is no fixed limit. Whoever sells many identical new goods or buys goods only for resale is usually considered commercial.

In detail

• Private: house clearance, flea market, used clothes from your own wardrobe, single occasional sales.
• Commercial: purchase for resale, many new goods, permanently the same items, reselling.
• Platforms: Vinted, eBay and Amazon report traders with many sales to the tax office (DAC7). Since 2023 platforms have reporting duties.
• Consequences: an unregistered business can mean a fine and back taxes.
• Legally safe: when in doubt rather register, especially as a minor with approval.

See also: Registering a business step by step, Online shop as a small business: duties