Free Bulk Code 128 Barcode Generator

What is Code 128?

Code 128 is a high-density linear barcode symbology that can encode the full ASCII character set. It is the most widely used barcode format in logistics, shipping (GS1-128), and warehouse inventory because it is compact and can encode letters, numbers and symbols.

Common Uses for Code 128

Shipping labels (UPS, FedEx, DHL use Code 128 variants)
Warehouse inventory and bin location tracking
Retail internal stock management
Healthcare specimen and patient ID labels

Code 128 vs GS1-128

Code 128 and GS1-128 use the same underlying symbology, but GS1-128 adds standardized Application Identifiers (AIs) that tell scanners what each part of the data means - for example (01) for a GTIN or (00) for an SSCC. If your supply chain partners require GS1-compliant data (common in retail, grocery and healthcare), use GS1-128 with the correct AIs. If you just need a compact barcode for internal tracking, plain Code 128 is simpler.

Code 128 Check Digit

Code 128 includes a built-in check character that the scanner uses to verify the barcode reads correctly. Unlike EAN-13 or UPC-A, you don't need to calculate this yourself - it is encoded automatically. The tool handles it for you, so every barcode you generate here is valid and scannable.

Code 128 Barcode Size Requirements

Code 128 is a high-density symbology, so it stays scannable even when printed small. As a rule, keep the narrowest bar (the X dimension) above 0.25mm and leave at least 10 times the X dimension of quiet space (white margin) on each side. On 4x6 shipping labels, Code 128 at scale 2-3 scans reliably with most warehouse scanners.

Code 128 Character Sets A, B and C

Code 128 has three subsets. Set A covers uppercase letters, digits and control characters; Set B adds lowercase letters; Set C packs two digits into one character, making pure numbers about half as wide. An encoder shifts between sets as your data demands - a value like INV-2026-0417 mixes B and C automatically. This is why Code 128 beats Code 39 for mixed data: the encoder always picks the cheapest representation for each part of your string.

Code 128 vs Code 39: which to choose

For new label systems, Code 128 is the better default: it encodes lowercase and full ASCII, is roughly 30-40% more compact, and every modern scanner reads it. Code 39 remains right only when a customer specification, government standard or ancient scanner fleet mandates it. If your values are purely numeric and very long, Interleaved 2 of 5 is denser than both - but for anything containing letters or dashes, Code 128 wins.

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Frequently Asked Questions

What is Code 128 used for?

Code 128 is used for shipping labels, logistics tracking, warehouse inventory and any application needing compact alphanumeric barcodes.

Can I batch generate Code 128 barcodes?

Yes, this tool generates multiple Code 128 barcodes at once from a list of values, so you can print a whole batch on one sheet.

Is Code 128 the same as GS1-128?

GS1-128 is a specific application standard of Code 128 used for supply chain. It uses the same symbology but adds GS1 application identifiers.

Does the generator work offline?

Yes, barcodes are generated locally in your browser - your data never leaves your device.

How much data can a Code 128 barcode hold?

Code 128 is variable length with no hard limit, but labels get wide fast: roughly 20-25 alphanumeric characters is a practical maximum for a shipping-label-width barcode, and 10-15 keeps labels compact and easy to scan.

Do I need to choose Code 128 A, B or C?

No. Modern encoders (including this one) automatically switch between subsets A, B and C to produce the shortest possible symbol for your data - you just type the value and the code is optimized for you.