"Barcode" is a catch-all word for dozens of different symbologies, each designed for a specific job. A supermarket checkout scanner, a shipping label printer, and a medical device engraving tool are all technically making "a barcode," but they're using completely different formats under the hood. Picking the wrong one means a scanner that can't read your label, a retailer that rejects your product listing, or a code that simply can't fit the data you need. This guide breaks down the symbologies our free barcode generator supports, in plain language, so you can pick correctly the first time.
Retail barcodes: EAN-13, EAN-8, UPC-A, UPC-E
These are the numeric barcodes printed on nearly every packaged product you buy. EAN-13 (European Article Number, despite the name it's used worldwide) encodes 13 digits and is the global retail standard outside North America. UPC-A is its 12-digit American and Canadian cousin; the two are close enough that virtually every modern scanner reads both interchangeably. EAN-8 and UPC-E are compressed variants for small packages, like a stick of gum or a lipstick tube, where a full 13-digit code would be physically too wide to print legibly.
All four share the same rule: the final digit is a checksum calculated from the digits before it, which is why our generator can auto-calculate the check digit for you if you only enter 12 digits for EAN-13 (or 11 for UPC-A). Note that a barcode you print yourself is only "correct" in format; if you intend to sell through a retailer, you'll need a unique number, which normally means registering with GS1 to avoid duplicating another product's code.
Book and periodical codes: ISBN, ISSN
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Create yours freeISBN and ISSN are really just EAN-13 barcodes with a reserved number prefix, one for books and one for magazines/journals. If you're self-publishing a book or printing a periodical, you'd use these instead of a generic EAN-13, since retailers and library systems specifically expect the ISBN/ISSN prefix structure to identify the item as a publication rather than a general retail product.
Logistics and shipping: Code128, GS1-128, ITF-14
Code128 is the workhorse of shipping labels, internal asset tags, and warehouse operations. Unlike EAN/UPC, it can encode the full ASCII character set (letters, numbers, and symbols) at high density, and it requires no registration, making it the default choice whenever you need to label something for internal tracking rather than retail sale.
GS1-128 is Code128 with a standardized data structure layered on top, using Application Identifiers (AIs) to encode structured fields like batch number, expiry date, or quantity within a single scan, in a format that's machine-parseable across any GS1-compliant supply chain system. ITF-14 (Interleaved 2 of 5) is specifically used to mark shipping cartons, encoding a 14-digit case-level identifier that's typically the EAN-13 of the individual product with a packaging indicator added.
General-purpose linear barcodes: Code39, Code93, Codabar, MSI
Code39 remains common in industrial and government settings, including some ID badges and inventory systems, largely due to legacy adoption rather than any technical advantage; it's less space-efficient than Code128 for the same data. Code93 is a denser evolution of Code39 with built-in checksums for better reliability. Codabar shows up in libraries and blood banks, again mostly for historical compatibility reasons. MSI is used almost exclusively for shelf-inventory and warehouse racking labels where a simple, purely numeric code is all that's needed.
2D symbologies: DataMatrix, PDF417, Aztec, QR Code
Two-dimensional barcodes pack data into a square or rectangular grid rather than a single line, which lets them store far more information in a much smaller physical footprint. DataMatrix is the standard for marking small parts, since it stays scannable even etched directly onto a component a few millimeters across, which is why it's the default in electronics and medical device serialization.
PDF417 is a stacked linear symbology capable of storing a large block of structured data offline, no database lookup required, which is why it's used on driver's licenses, boarding passes, and shipping manifests. Aztec Code is compact and doesn't require a surrounding quiet zone, making it a favorite for airline and train e-tickets printed on small paper stubs or shown on a phone screen. QR Code is the most recognizable 2D format and the best general-purpose choice whenever the code needs to be scanned by an ordinary consumer smartphone camera rather than dedicated hardware.
Postal codes and other specialty symbologies
Postal services use their own dedicated barcode formats optimized for high-speed sorting machinery: USPS PostNet and Intelligent Mail Barcode in the US, Royal Mail 4-State in the UK, and equivalents from Australia Post and Japan Post. These aren't something most businesses need to generate themselves, but they matter if you're producing mail pieces that need automated sorting compatibility. Micro QR Code and MicroPDF417 exist as space-saving variants of their full-size counterparts for situations with very little available print area but still needing 2D-level data density.
GS1 DataMatrix, GS1 QR Code, and GS1 DataBar
GS1 has extended its structured Application Identifier system beyond Code128 into 2D formats. GS1 DataMatrix and GS1 QR Code let you pack the same structured retail/logistics data (batch, expiry, serial number) into a much smaller area than GS1-128 would need, which matters for small pharmaceutical packaging where space is at a premium. GS1 DataBar (in Omni, Expanded, and Limited variants) is a compact linear alternative to EAN/UPC aimed at very small retail items, like loose produce stickers, where a full-size EAN-13 barcode simply won't fit.
How to choose the right symbology for your project
Start with the question of who's scanning it and why. If it's a retail product going through a store checkout, you almost certainly need EAN-13/UPC-A and, if selling internationally or online, a legitimate GS1-registered number. If it's an internal shipping label, pallet tag, or asset tracker, Code128 or GS1-128 is the practical default with no registration hassle. If you're marking a small physical part or need offline structured data (like a boarding pass), reach for DataMatrix or PDF417. If a consumer is scanning it with their own phone, whether for a menu, a link, or a ticket, QR Code is almost always the better fit given how universally smartphone cameras support it.
Our barcode generator supports all of the symbologies covered here, more than 30 in total, generated entirely in your browser with a live preview, adjustable bar width and height, quiet-zone margin, and custom colors, so you can try a few formats side by side before committing to print.
Frequently asked questions
What is the difference between EAN-13 and UPC-A?
UPC-A is a 12-digit code used mainly in the United States and Canada, while EAN-13 is its 13-digit international superset used almost everywhere else. Any EAN-13 scanner can read a UPC-A code (it is simply treated as EAN-13 with a leading zero), which is why most modern retail systems support both.
Which barcode type should I use if I just need to label boxes for shipping?
Code128 is the most common choice for shipping labels, pallets, and internal logistics because it encodes the full ASCII character set compactly and needs no registration. GS1-128 is the same symbology with a standardized data structure layered on top, useful if you need to encode things like batch numbers or expiry dates in a format partners can parse automatically.
Do I need to register with GS1 to make a barcode?
Only if you are selling a retail product through stores that require a globally unique EAN/UPC number, which does require GS1 membership and a fee. For internal use, shipping labels, asset tracking, or 2D codes like DataMatrix and QR Code that carry your own data, no registration is required and you can generate them freely.
When should I use a 2D barcode like DataMatrix or PDF417 instead of a QR code?
DataMatrix is preferred for very small parts marking (electronics, medical devices) because it stays readable at a tiny physical size. PDF417 is used where a large amount of structured data must be stored offline, such as driver's licenses and boarding passes. QR Code is the best general-purpose choice for anything a consumer smartphone needs to scan, since camera-based QR scanning is universal.