QR Code & Barcode Types Reference
QR codes and barcodes bridge the physical and digital worlds. This page summarizes common symbologies, capacities, use cases, QR error correction levels and the standard WiFi QR format.
Common Symbologies
| Symbology | Type | Capacity | Best For |
|---|---|---|---|
| QR Code | Matrix 2D code | 7,089 numeric / 4,296 alphanumeric / 2,953 bytes | URLs, payments, contact cards, WiFi connections, mobile |
| Micro QR | Compact matrix 2D code | 35 numeric / 21 alphanumeric | Space-constrained parts, IC labels |
| CODE128 | Linear barcode | ASCII 128 charset, high density | Logistics, warehousing, serial numbers |
| EAN-13 | Linear barcode | 13 digits incl. checksum | Retail products, book ISBN |
| UPC-A | Linear barcode | 12 digits incl. checksum | North American retail products |
| CODE39 | Linear barcode | Digits, uppercase, some symbols | Industrial, defense, asset labels |
| ITF-14 | Linear barcode | 14 digits | Outer case packaging, logistics units |
QR Code Error Correction
| Level | Recovery | Suggested Use |
|---|---|---|
| L | ~7% | Short content, clean scan env |
| M | ~15% | Default, balanced capacity/recovery |
| Q | ~25% | Average print quality, higher recovery |
| H | ~30% | Logo overlay, harsh environments |
Frequently Asked Questions
Which QR Code error correction level should I use?
Default to M (15% recovery) for the best balance of capacity and redundancy. Use H (30%) when placing a logo in the center or printing on low-quality surfaces. Use L (7%) only for short content in clean scanning environments. Higher levels produce denser patterns for the same payload.
What is the difference between 1D and 2D codes?
1D barcodes store data in one direction only, carry little data (often tens of characters), require a specific scan angle and are suited for short codes like SKUs and tracking numbers. 2D codes store data both horizontally and vertically, offer large capacity and error recovery, and can be read by phone cameras at any angle, making them ideal for URLs, payments and contact cards.
What is the WiFi QR code format?
The standard format is `WIFI:T:<auth>;S:<SSID>;P:<password>;H:<hidden>;;`, e.g. `WIFI:T:WPA;S:MyNetwork;P:MyPassword;;`. Phones can scan it and connect automatically without typing credentials.
Can barcodes contain Chinese characters?
Common 1D barcodes (CODE128, EAN, UPC) only encode digits, letters or ASCII symbols and cannot represent Chinese directly. Use a QR Code for Chinese text because it supports UTF-8 encoding.