At first glance, barcodes and QR codes look like they do the same thing: encode data in a scannable image. But they're built for different jobs, store different amounts of data, and are read by different devices. Choosing the wrong one for your use case means either leaving capability on the table or creating something incompatible with the readers your users actually have.
How Traditional Barcodes Work
A traditional barcode (technically a "1D barcode" or "linear barcode") encodes data in a pattern of parallel bars and spaces of varying widths. The scanner reads the barcode in a single horizontal sweep. This one-dimensional design means barcodes can only encode a limited amount of data — typically a numeric or short alphanumeric string — and must be read with a dedicated laser scanner or a camera held straight in front of the code.
Several barcode symbologies (formats) exist, each optimized for a specific use:
- EAN-13 / UPC-A — the standard format for retail products worldwide. 13 digits (EAN) or 12 digits (UPC). Every product on a grocery store shelf has one of these.
- Code 128 — encodes the full ASCII character set, supports variable length, and is widely used for shipping labels, inventory, and logistics.
- Code 39 — older alphanumeric format; still used in some industrial and healthcare settings.
- ITF (Interleaved 2 of 5) — numeric only; used for outer carton shipping boxes.
- EAN-8 — a compact 8-digit version of EAN-13 for small packages.
The Barcode Generator on DevToolShack supports all of these formats. You can generate any of them, customize size and colors, and download as PNG — no account, no sign-up.
How QR Codes Work
A QR code (Quick Response code) is a 2D matrix code. Instead of parallel bars, it uses a grid of black and white squares arranged in a square pattern. Because it's two-dimensional, a QR code can encode far more data than a traditional barcode — up to around 3,000 alphanumeric characters — and can be read from any angle, even if partially damaged (thanks to built-in error correction).
Modern smartphones read QR codes natively through the camera app without any additional software. This is the key practical difference: you don't need a dedicated scanner. That's why QR codes became the default for consumer-facing applications after smartphone penetration made them universally accessible.
For a deeper look at what QR codes can encode beyond URLs — including Wi-Fi credentials, TOTP 2FA setup, vCards, and deep links — see QR Codes for Developers: When, Why, and How to Generate Them.
Capacity and Data Comparison
| Format | Type | Max data | Scanner required |
|---|---|---|---|
| EAN-13 | 1D | 13 digits | Barcode scanner or camera |
| Code 128 | 1D | ~48 chars (typical) | Barcode scanner or camera |
| QR Code | 2D | ~3,000 alphanumeric chars | Smartphone camera (native) |
Which to Use: A Decision Guide
Use a traditional barcode when...
- You're labeling retail products. EAN/UPC codes are required by retailers and point-of-sale systems. If you're selling a physical product in a store, you need an EAN-13 or UPC-A, registered with GS1 for a globally unique prefix.
- You're working with shipping or logistics. Code 128 is the standard for shipping labels (FedEx, UPS, USPS all use it). Your warehouse management software almost certainly expects a linear barcode.
- Your readers are dedicated scanners. Industrial environments with laser scanners, checkout counters, and warehouse guns are built around 1D barcodes. They're fast, reliable, and don't require the wider field of view a QR code needs.
- The data fits. If you're encoding a product SKU, a numeric ID, or a short reference number, a barcode is smaller, simpler, and prints more cleanly at small sizes.
Use a QR code when...
- You're encoding a URL. QR codes are the standard for linking physical objects to web content: restaurant menus, product pages, event registration, payment links.
- You need 2FA setup. TOTP authenticator apps (Google Authenticator, Authy) use an
otpauth://URI encoded in a QR code to set up time-based one-time passwords. This is the standard onboarding flow for 2FA. - You're sharing Wi-Fi credentials. A QR code can encode a
WIFI:URI that iOS and Android both recognize — scanning it connects the device without typing a password. - Your users have smartphones. Consumer-facing applications where users scan with their personal phones should always use QR codes. No app download, no dedicated hardware.
- You need error tolerance. QR codes can be read even when up to 30% of the code is obscured or damaged (at the highest error correction level). For outdoor signage, stickers, or printed materials that might get worn, this resilience matters.
Error Correction in QR Codes
QR codes have four error correction levels: L (7% recovery), M (15%), Q (25%), and H (30%). Higher error correction means the code can still be read even with more damage — but it also makes the code denser (more squares) and therefore harder to scan at small sizes. For most URL use cases, level M is a good default. For codes that will be printed on materials subject to wear, use Q or H. For codes embedded in a logo design, you need H.
Generating Both Formats Free
DevToolShack has separate tools for each. The QR Code Generator supports URLs, plain text, Wi-Fi, 2FA (otpauth), vCard, and email — with customizable size and error correction level, downloadable as PNG or SVG. The Barcode Generator supports EAN-13, EAN-8, UPC-A, Code 128, Code 39, and ITF, with size and color controls. Both run entirely in the browser; nothing is uploaded or stored.