Barcode Generator

How to Use the Barcode Generator

1. Enter the data to encode - digits, letters, or both, depending on the symbology. EAN-13 and UPC-A accept only digits; CODE128 accepts the full ASCII range; CODE39 accepts uppercase letters, digits, and a small set of symbols.
2. Choose a barcode format - select the 1D symbology that matches your use case. Retail products use EAN-13 internationally or UPC-A in North America. Warehousing and logistics generally use CODE128 or CODE39. Outer cartons use ITF-14.
3. Adjust appearance - sliders control bar width (module width) and bar height. Toggle the human-readable text below the bars on or off, set the font size, and pick fill and background colors. For professional printing, keep the bars pure black on pure white - colored bars can confuse older scanners.
4. Download - export as a 2x-resolution PNG for general use or SVG for vector workflows. SVG is preferred when the barcode will be scaled (packaging layouts, large signs) because it keeps module edges crisp at any size.

What 1D Barcodes Are and How This Tool Renders Them

A 1D (linear) barcode encodes characters as a sequence of alternating black bars and white spaces of varying width. A scanner reads the light-and-dark pattern horizontally and translates the width sequence back into characters via a lookup table defined by the symbology. This tool uses the JsBarcode library under the hood, which is a mature open-source JavaScript implementation that covers the major 1D symbologies. For PNG output, the library draws onto an HTML <canvas> element; for SVG, it produces an inline <svg> with one <rect> per bar. The result matches the symbology specifications exactly - you can hand the output to a Zebra printer or a commercial offset press and it will scan on any ISO/IEC 15423-compliant reader.

Barcode rendering runs entirely as client-side JavaScript. Your encoded data never leaves your browser - there is no backend call, no analytics event with your SKU or tracking number, and no external image generation service. This matters for businesses generating sensitive internal IDs: a part number or internal routing code entered here is visible only to you. Check the browser\'s DevTools Network tab to confirm zero outbound requests fire while you edit the data.

Which Symbology Fits Which Job

• CODE128 - the workhorse for shipping labels, asset tags, and internal logistics. Encodes the full 128-character ASCII set with good information density.
• EAN-13 - the 13-digit international retail product barcode managed by GS1. Required on any product sold through European, Asian, South American, and most African retailers.
• UPC-A - the 12-digit North American retail barcode, also GS1-managed. Required on products sold through US and Canadian retail chains; EAN-13 is a superset (US/Canada compatible) and increasingly the default.
• EAN-8 - a compact 8-digit variant for small products where a full EAN-13 does not physically fit (cosmetics, candy).
• CODE39 - alphanumeric barcode historical to automotive (VIN component tags), defense, and healthcare. Lower density than CODE128 but widely scannable on older equipment.
• ITF-14 - 14-digit numeric code used on corrugated outer cartons and shipping cases; encodes the GTIN-14 for the carton including a packaging indicator digit.
• MSI - numeric, commonly found on warehouse shelf labels and pallet markings. Less common in retail.
• Pharmacode - a binary numeric code (3 to 131,070) used on pharmaceutical packaging for line-inspection equipment to verify the correct insert made it into the box.

Pitfalls, Check Digits, and Print-Size Rules

EAN and UPC codes include a modulo-10 check digit that validates the preceding digits. This tool calculates the check digit automatically when you enter one fewer digit than the code requires - so enter 12 digits for EAN-13 or 11 for UPC-A and let the tool append the check. Entering all 13/12 with a wrong check digit will be rejected. For CODE128 and CODE39, most generators auto-insert start/stop characters and internal check characters (CODE128 always, CODE39 optional with the "mod 43" variant); do not include them in the input. The GS1 General Specifications define minimum physical dimensions: a standard EAN-13 must be printed at 80%-200% of nominal size (nominal = 37.29 mm x 25.93 mm); printing below 80% risks scan failure. The "X-dimension" (narrowest bar width) should be at least 0.264 mm for general retail. Bar height should be at least 15% of the code width to allow scanner beam misalignment. Include a 10X quiet zone (silent margin) of white space to the left and right - cutting into the quiet zone is the most common cause of unscannable retail labels.

GS1, Check Digits, and the 1D Barcode Ecosystem

EAN, UPC, ITF-14, and GTIN-based codes are part of the GS1 General Specifications, an international standard maintained by GS1 that assigns company prefixes so every product in the world gets a globally unique identifier. To legally use EAN-13 or UPC-A on a product sold through retailers, you must obtain a GS1 company prefix from your national GS1 office (about $30-$250 initial fee plus annual dues depending on company size). Consumer sellers sometimes buy reseller UPCs for $5-10; these technically resolve but may be rejected by major retailers, who verify prefix ownership through the GS1 GEPIR database. For internal use only - warehouse asset tracking, production-line routing, non-retail distribution - you can generate any codes you want under CODE128, CODE39, or custom numbering without GS1 involvement. Code 128 is formalized by ISO/IEC 15417; Code 39 by ISO/IEC 16388; ITF-14 and EAN/UPC by ISO/IEC 15420. All are open standards.

Comparison to BarTender, NiceLabel, and Label-Printer Firmware

Commercial label software (BarTender, NiceLabel, Zebra ZebraDesigner, Seagull Scientific) integrates barcode generation into serialized printing workflows - pull variable data from Excel, SQL, or SAP and stream labels to thermal printers at hundreds per minute. Those are the right tool for production lines and warehouses. For single-code needs, design mockups, or prototyping a new product barcode, a browser generator like this one is faster and free. Open-source command-line tools like Barcode (GNU), ZINT, and the Python barcode library produce identical output and are scriptable for automated batch generation. This tool\'s niche is immediate, on-screen generation with live customization and clean PNG/SVG export - useful for designers producing packaging comps, small businesses ordering a first production run, or anyone prototyping internal label formats. The generated SVG drops directly into Illustrator, InDesign, Affinity Designer, or Figma without format conversion. For commercial retail sale, pair the generated code with a legitimate GS1 company prefix.