A traditional barcode (the parallel-line kind on product packaging) only stores a short number — it's a lookup key. Scan it, and the register looks up that number in a database to find the price and product name. The barcode itself knows nothing.
The real difference: where the data lives
A QR code carries the actual data — a full URL, a Wi-Fi password, a whole vCard — inside the pattern itself. There's no database lookup required. Scan a QR code offline, and it still works, because everything needed is printed right there.
Why QR codes fit small business use cases better
Retail barcodes require you to register a number in a product database (UPC/EAN systems, POS integration) — overkill for a menu, a Wi-Fi network, or a contact card. A QR code needs no registration, no database, no account: you generate it and it works immediately.
Capacity is the other big gap
A standard barcode holds roughly 20 characters. A QR code can hold thousands of characters — that's why a QR code can encode an entire vCard with a name, phone, email, and address, while a barcode physically cannot fit that much information.
When you'd still want a barcode
If you're selling physical retail products through standard point-of-sale and inventory systems, barcodes remain the industry standard — that infrastructure is built around database lookups, not self-contained data. Use QR codes for anything that doesn't need a product database behind it.