How to Generate Barcodes Online

What Are Barcodes?

A barcode is a machine-readable representation of data using parallel lines of varying widths and spacings. Introduced commercially in the 1970s for grocery checkout, barcodes now appear on virtually every manufactured product, shipping label, library book, and event ticket worldwide.

The pattern of bars encodes a string of numbers or characters. A barcode scanner reads the pattern by measuring reflected light and decodes it back into the original data. This process takes milliseconds and is far more reliable than manual data entry — barcode scanning has an error rate of roughly 1 in 3 million compared to 1 in 300 for human keyboard entry.

Despite the rise of QR codes, traditional one-dimensional barcodes remain the standard for retail, logistics, healthcare, and manufacturing. They are simpler, faster to scan, and supported by every point-of-sale system on the planet.

Common Barcode Types

Different industries and use cases call for different barcode formats:

• EAN-13: The international standard for retail products. 13 digits that encode country, manufacturer, product, and a check digit. Used everywhere outside North America.
• UPC-A: The North American retail standard. 12 digits. Functionally equivalent to EAN-13 (a UPC-A is an EAN-13 with a leading zero).
• Code 128: A high-density format that encodes all 128 ASCII characters. Widely used in shipping labels, inventory management, and internal tracking where the data includes letters and numbers.
• Code 39: An older alphanumeric format still used in automotive, defense, and healthcare. Less dense than Code 128 but simpler to implement.
• ITF-14: Used for outer carton labeling in logistics. Encodes 14 digits and is designed to be printed on corrugated cardboard at large sizes.
• Pharmacode: Used in pharmaceutical packaging to encode medication identifiers. Supports numeric data with a compact footprint.

For most general purposes, Code 128 is the best choice. It handles any combination of letters and numbers with excellent data density. For retail products that need a standard product identifier, EAN-13 or UPC-A is required.

Creating Barcodes

Generating a barcode requires three decisions: the format (which type), the data (what to encode), and the output parameters (size, resolution, colors).

For product barcodes, the data is typically a GTIN (Global Trade Item Number) assigned by GS1, the organization that manages product identification standards. You cannot invent a random number and put it on a retail product — the number must be registered and unique.

For internal use (warehouse tracking, asset labels, event tickets), you can encode any data you choose. The only constraint is the character set supported by your chosen barcode format.

Output parameters matter for printability. A barcode that looks fine on screen may not scan when printed at small sizes or on low-resolution printers. Key guidelines:

• Minimum bar width should be at least 0.264mm (1 mil) for reliable scanning.
• Include quiet zones (blank margins) on both sides — typically 10 times the narrowest bar width.
• Print at 300 DPI or higher for thermal and laser printers.
• Dark bars on a light background scan best. Black on white is the gold standard.

Barcode vs QR Code

One-dimensional barcodes and two-dimensional QR codes serve different purposes. Barcodes encode a short string (typically 8-30 characters) in a compact horizontal strip. QR codes encode up to 4,296 characters in a square grid and can store URLs, vCards, Wi-Fi credentials, and other structured data.

Use a barcode when you need fast scanning of a short identifier — product lookup, inventory check-in, or ticketing. Use a QR code when you need to encode a URL or a large block of text and the scanner is a smartphone camera rather than a dedicated laser scanner.

In retail and logistics, barcodes will remain dominant because the scanning infrastructure is built around them. Handheld laser scanners and fixed-mount readers in conveyor systems are optimized for one-dimensional codes.

Generate Barcodes with Our Free Tool

Our Barcode Generator supports multiple formats including Code 128, EAN-13, UPC-A, Code 39, and ITF-14. Enter your data, pick the format, and download a print-ready barcode as PNG or SVG.

The generator runs entirely in your browser. Your data stays on your device and is never sent to any server. You can customize bar width, height, font size, and whether to display the human-readable text below the bars.

Whether you need a single barcode for an asset tag or a batch of labels for inventory, the tool produces scannable output ready for printing in seconds.