QR Code vs Barcode
Traditional barcodes (like UPC/EAN codes on retail products) are one-dimensional — a single row of lines holding roughly 20-25 numeric characters. QR codes are two-dimensional, hold up to thousands of alphanumeric characters, and can be scanned from any angle rather than needing a straight-on pass.
The practical difference shows up immediately in what each can encode: a 1D barcode is essentially a lookup key (a product ID that a database looks up), while a QR code can carry the actual content — a full URL, a complete vCard, a Wi-Fi password — with no database lookup required.
1D barcodes still make sense for retail point-of-sale, where speed and a tiny print footprint matter more than data capacity. QR codes took over almost everywhere content needs to travel with the code itself: marketing, ticketing, payments, contact sharing.
Reading direction is another concrete difference: a 1D barcode scanner needs a reasonably straight, level pass across the lines, which is why cashiers sometimes rotate a product to line it up correctly. A QR code's three-corner finder pattern lets a scanner determine orientation instantly, so it reads correctly held upside-down, sideways, or at a steep angle — no repositioning needed.
Damage tolerance also differs sharply. A 1D barcode has essentially no error correction, so a torn, smudged, or partially obscured barcode very often fails to scan outright. QR codes build in error correction as a core part of the spec (see that entry), letting a code with real damage, up to roughly 30% at the highest level, still decode correctly.
The two formats aren't in competition so much as suited to different jobs: 1D barcodes remain the standard for high-speed retail checkout, where the infrastructure (scanners, databases) is already built around them and swapping formats industry-wide would cost far more than it would save. QR codes dominate everywhere a business wants to hand information directly to the public, without requiring access to a private lookup database on the other end.