Barcode Generator - Create Code 128, EAN-13, UPC-A Barcodes

1. Choose Barcode Standard (Symbology)

Barcode Format - which standard to use?

Code 128: A high-density 1D barcode (one-dimensional barcode - a barcode made of vertical bars and spaces) that encodes the full ASCII character set including letters, numbers, and symbols. Widely used in warehousing, shipping labels, and inventory management because it packs a lot of data into a small space.

Barcode Value - letters and numbers accepted

2. Visual Customization

Human-Readable Text Show numbers below the barcode bars

In a retail setting, human-readable text lets cashiers and stock teams manually verify a code if a scanner fails to read it.

Bar Width (element thickness) - controls how thick each vertical bar is

Bar Height - total height of the barcode in pixels

100

3. Live Barcode Preview

Enter a value above to generate your barcode

SVG = vector format, infinitely scalable, ideal for commercial thermal label printers. PNG = raster image (pixel-based), suitable for websites and word processing documents.

The Complete Guide to Product Identification and Retail Barcode Standards

Everything small business owners, e-commerce sellers, and logistics professionals need to know about choosing the right barcode for their products.

What is the difference between UPC-A, EAN-13, and Code 128? +

These three barcode formats are called symbologies - meaning they are distinct systems with their own rules for encoding data as vertical bars and spaces. Each was designed for a specific industry context.

UPC-A (Universal Product Code - Version A) is a 12-digit numeric-only standard developed in the United States in the 1970s for North American retail checkout. Every product sold on a shelf at Walmart, Target, or a US grocery store carries a UPC-A barcode. The Uniform Code Council (now GS1 US) manages the issuance of UPC company prefixes.

EAN-13 (European Article Number - 13 digit) is the international counterpart to UPC-A, adding a 13th digit at the front (the country or flag code). A UPC-A barcode is actually a subset of EAN-13: any modern scanner that reads EAN-13 will also read UPC-A. If you sell products internationally - including on Amazon's non-US marketplaces - you need EAN-13 barcodes.

Code 128 is a flexible, high-density barcode that can encode the full ASCII character set: uppercase and lowercase letters, numbers, punctuation, and special characters. It has no fixed length limit. Code 128 is the dominant format in shipping and warehousing - FedEx, UPS, and USPS tracking barcodes are all Code 128. For internal inventory management, Code 128 is the most practical choice because you can encode meaningful alphanumeric identifiers like "SHIRT-RED-LG-2024" rather than being restricted to pure numbers.

How does the check digit protect retail scanners from misreads? +

A check digit is a single calculated number appended to the end of a barcode value. It exists entirely as a mathematical safeguard - it carries no product data. Its only job is to let a scanner instantly verify that the barcode it just read was decoded correctly.

For UPC-A and EAN-13, the check digit is computed using the Modulo 10 (Luhn-style) algorithm. Here is how it works for a 12-digit UPC-A: Take the first 11 digits. Multiply each digit in an odd position (positions 1, 3, 5, 7, 9, 11) by 3. Multiply each digit in an even position (positions 2, 4, 6, 8, 10) by 1. Sum all the results. The check digit is the number you must add to that sum to reach the next multiple of 10. For example, if the sum is 73, the check digit is 7 (because 73 + 7 = 80).

When a laser scanner at a grocery checkout reads a barcode, it immediately recalculates this check digit from the bars it decoded and compares it to the digit printed at the end. If they match, the scan is accepted. If they do not match - perhaps because the barcode was partially obscured or the bars were printed poorly - the scanner rejects the read and signals the cashier to try again. This single mathematical step eliminates the vast majority of phantom or corrupted scan errors in high-volume retail environments. This tool automatically calculates and appends the correct check digit for you when you enter 11 digits for a UPC-A or 12 digits for an EAN-13.

Why are SVG vector barcodes better than standard image files for printing labels? +

The difference between vector graphics (SVG) and raster graphics (PNG, JPG) is fundamental to print quality, especially for barcodes. Understanding it can save you a costly batch of unscannable labels.

A raster image stores your barcode as a fixed grid of colored pixels. If you create a PNG barcode at 200 pixels wide and then tell your label printer to print it at 400 pixels wide, the printer software must invent the missing pixels - a process called interpolation or upscaling. This blurs the sharp edges of each bar, producing soft gray fringe pixels along every bar edge. Retail scanners depend on detecting the precise optical contrast between a dark bar and the white space next to it. Blurry edges reduce contrast, causing misread rates to climb dramatically. On commercial thermal transfer printers - the standard for warehouse and retail labels - even a small amount of blurring can render an entire print run unscannable.

An SVG file stores your barcode as a set of mathematical descriptions: "draw a rectangle from coordinate (x1, y1) to coordinate (x2, y2)." There are no pixels. When your printer renders the SVG at any size - whether it is a tiny 1-inch label or a large 4-by-6-inch shipping label - it re-calculates the exact position of each bar edge at the printer's native resolution (often 300 or 600 dots per inch). The result is perfectly sharp bars with razor-clean edges at any scale. For commercial printing, SVG is always the professional-grade choice. Use PNG only when uploading a barcode image to a website, inserting it into a Word document, or sending it in an email where the print path is not the primary concern.

Can I use these generated barcodes to list products on Amazon or major retailers? +

This is one of the most important questions for any small business owner entering retail channels, and the answer requires a clear distinction between generating a barcode image and owning a globally registered product identifier.

This tool generates the visual barcode artwork - the actual scannable bars and human-readable numbers - from any number you provide. The barcode artwork itself is not the regulated part. What major retailers and Amazon regulate is the GTIN (Global Trade Item Number) that the barcode encodes. A GTIN is essentially a globally unique product ID issued by GS1, the international standards body that manages product identification.

For Amazon specifically: Amazon's Brand Registry and standard product listings require that the UPC or EAN you list matches a GS1-registered company prefix. Amazon actively cross-references barcodes against the GS1 database. If you enter a 12-digit UPC number that was not purchased from GS1 (or an authorized GS1 reseller), your listing may be suppressed or rejected. To sell on Amazon with your own branded products, you need to purchase a GS1 Company Prefix from GS1 US (gs1us.org) for the United States, which grants you the right to assign GTINs to your specific products. The numbers you then assign to your products are what you would enter into this tool to generate the physical barcode artwork for your labels.

For internal use, shipping, and inventory: Code 128 barcodes generated with any number you choose are perfectly valid for warehouse management, internal inventory tracking, and shipping label workflows. You do not need GS1 registration for internal operations - only for entry into external retail commerce systems.

What is a 1D barcode and how is it different from a QR code? +

The barcodes generated by this tool are 1D barcodes - meaning "one-dimensional barcodes." They encode data in a single horizontal dimension: data is represented by the varying widths of vertical bars and the white spaces between them. A scanner reads the barcode by passing a laser or camera across a single horizontal line through the bars.

A QR code (Quick Response code) is a 2D barcode - "two-dimensional." It encodes data in both horizontal and vertical patterns - the grid of black and white squares you recognize from restaurant menus and mobile payment apps. Because 2D barcodes use two dimensions, they can store far more data in a smaller physical space (QR codes can encode thousands of characters versus around 20-80 characters for most 1D barcode applications). QR codes can also be read from any angle and can still be decoded even if up to 30% of the symbol is damaged.

Despite the advantages of QR codes, 1D barcodes remain the global standard for retail product identification. Every laser scanner at every checkout counter in every grocery store and retail chain worldwide is built to read 1D barcodes. The installed base of retail scanning infrastructure - representing billions of dollars of equipment - is designed around Code 128, UPC, and EAN formats. For any product entering a physical retail supply chain, a 1D UPC-A or EAN-13 barcode is not optional - it is a requirement.