Barcode Generator
Generate high-quality custom barcodes in seconds. Select from multiple barcode symbologies, customize sizes and colors, and download as PNG or SVG.
Linear Barcode Symbology Specifications (CODE128, EAN, UPC)
Linear barcodes (one-dimensional or 1D barcodes) are optical machine-readable representations of data composed of parallel black bars and white spaces of varying widths. Governed internationally by GS1 and ISO standards, barcodes are the ubiquitous technology powering retail points of sale, logistics inventory tracking, parcel shipping labels, and asset identification.
Our Barcode Generator supports all major international symbologies:
- CODE128 (ISO/IEC 15417): The most versatile high-density alphanumeric symbology, capable of encoding all 128 ASCII characters. Widely used in shipping, packaging, and warehouse logistics.
- EAN-13 & EAN-8 (ISO/IEC 15420): The International Article Number standard used on retail consumer products worldwide outside North America.
- UPC-A & UPC-E: The Universal Product Code standard ubiquitous across grocery and retail point-of-sale systems in the United States and Canada.
- CODE39: Widely used in automotive, defense, and healthcare supply chains.
- ITF (Interleaved 2 of 5): Compact numeric barcode standard used for corrugated shipping cartons.
Modulo-10 Checksum Calculation in Barcodes
Retail barcodes (EAN and UPC) incorporate a mandatory Modulo-10 Check Digit as their final numeral to prevent scanner read errors. The checksum is computed by weighting alternating digits by 1 and 3, summing the products, and calculating the remainder modulo 10. Our generator automatically calculates and appends correct check digits, preventing invalid label printing.
High-Resolution Vector SVG vs Bitmap PNG Printing
In industrial label printing, raster images (like JPEGs or low-res PNGs) can produce fuzzy, anti-aliased bar edges that cause laser barcode scanners to fail. Our generator renders barcodes in scalable SVG vector format, guaranteeing crisp, mathematically straight edges that print with 100% optical clarity on thermal label printers (Zebra, Dymo, Brother).
Client-Side Offline Generation
Generate inventory labels, book ISBN tags, and retail product barcodes privately without sending stock numbers or proprietary SKU catalogs to external cloud endpoints.
Symbology Architectures: Code 128 Character Sets vs EAN-13 Check Digit Math
Linear one-dimensional barcodes represent encoded alphanumeric data through alternating optical patterns of parallel bars and spaces of varying widths. The most versatile industrial standard is Code 128, which supports all 128 ASCII characters through three dynamic character subsets (Subset A for control characters and uppercase, Subset B for full alphanumeric text, and Subset C for double-density numeric pairs).
For retail point-of-sale applications, EAN-13 (European Article Number) mandates strict modulo-10 checksum validation. The 13th check digit is calculated by multiplying alternating digits by alternating weights of 1 and 3, summing the products, and calculating the difference from the next higher multiple of 10. Optical laser scanners reject any barcode failing this checksum before transmitting payloads to inventory databases.
Essential Barcode Printing & Quiet Zone Guidelines
- Quiet Zone Margins: Every barcode requires an unprinted blank margin on both horizontal flanks (at least 10 times the narrowest bar width) to prevent scanner synchronization failure.
- Contrast & Reflectance Ratios: Thermal barcode printers must maintain high optical reflectance contrast; black bars on a solid white matte substrate ensure optimal photodiode signal capture.
- Vector Scalability: Rendering barcodes as SVGs eliminates pixel blurring and anti-aliasing artifacts that cause laser scan misreads on physical label printers.
Frequently Asked Questions
CODE128 is strongly recommended for internal inventory, assets, and shipping labels because it encodes both letters and numbers with high density.
Yes. Export in SVG format or high-resolution PNG for crisp rendering on thermal ribbon and direct thermal printers.
UPC-A encodes 12 digits and is standard in North America. EAN-13 encodes 13 digits and is standard globally. A UPC-A is mathematically identical to an EAN-13 with a leading zero.
No. All symbology algorithms run 100% locally in your browser using client-side JavaScript.
Yes. You can configure line height, bar width, margins, and toggle human-readable text beneath the bars.