Barcode Generator

A practical guide to 1D barcodes

A linear (1D) barcode encodes a number or short string as a pattern of parallel bars and spaces of varying width. A scanner sweeps a beam across the symbol, measures the relative widths, and reconstructs the digits. The set of rules that maps characters to bar patterns is called a symbology. Different industries standardised on different symbologies, which is why this tool offers five of them — picking the right one matters more than it might seem.

Code 128 — the flexible workhorse

Code 128 encodes the full 128-character ASCII set and packs it densely, which is why it dominates shipping labels, logistics, and internal asset tracking. It has three sub-modes (A, B, C); mode C compresses pairs of digits into a single symbol, so a long numeric string takes very little width. If you are labelling boxes, shelves, or equipment with an alphanumeric code like SNAPTOOLS-2026, Code 128 is almost always the right answer.

EAN-13 and UPC — retail product codes

These are the GS1 retail symbologies you see on grocery items. EAN-13 carries 13 digits and is the worldwide standard; UPC-A carries 12 digits and is used in the US and Canada. Both end with a check digit computed from the preceding digits — a weighted modulo-10 calculation that lets a scanner detect a misread. EAN-8 is a compact 8-digit variant for tiny packages such as cosmetics or confectionery where a full EAN-13 simply will not fit.

Code 39 — legacy and industrial

Code 39 (also called Code 3 of 9) is one of the oldest alphanumeric symbologies. It encodes uppercase A–Z, digits 0–9, and a handful of symbols, and it frames each symbol with an asterisk start/stop character. It is less dense than Code 128 but remains mandated in some automotive, defence, and healthcare systems, so you will still meet it on older labels.

Print size and the quiet zone

Because the download is SVG, the barcode stays crisp at any size — but two rules keep it scannable. First, do not shrink the bars below the printer's reliable resolution; thin bars that blur together cause misreads. Second, leave a quiet zone: a clear margin of at least ten times the narrowest bar width on the left and right. Without it, scanners struggle to find where the symbol begins and ends.

When a 2D code fits better

A 1D barcode is perfect for a short number a laser scanner reads at speed, but it tops out at a few dozen characters. When you need to carry a URL, a batch of metadata, or anything a phone camera should act on, reach for a matrix code instead.

• • QR code generator — a 2D matrix that holds product pages, manuals, or thousands of characters.
• • QR code decoder — note that this reads QR codes, not 1D barcodes, which use a different scanner.
• • vCard QR code generator — encode supplier or contact details next to a product label as a 2D code.