Code 128 is a high-density linear barcode that encodes all 128 ASCII characters, with a mandatory check character. As GS1-128, it carries the shipment data on GS1 logistic labels. barKoder reads Code 128 and GS1-128, including deformed labels, in your iOS, Android and web apps.
| Type | Linear (1D), continuous symbology of variable length, readable in both directions |
| Character set and data | All 128 ASCII characters (0-127), plus byte values 128-255. Three code sets (A, B and C) and four function characters, FNC1 to FNC4. |
| Density | 11 modules per character, or 5.5 modules per digit in Code Set C, which packs two digits into one character. GS1-128 allows up to 48 data characters per symbol. |
| Check digit | One mandatory symbol check character. Every character is also self-checking through bar parity. |
| Standard | ISO/IEC 15417 (current edition 2007). GS1-128 is defined in the GS1 General Specifications. |
| Typical uses | Shipping and logistics labels (GS1-128), warehouse inventory, automotive parts and VINs, medication and patient labels |
Code 128 was created by Ted Williams and introduced by Computer Identics in 1981. It packs more data into a label than older codes such as Code 39 and can encode the full ASCII set. Every character is 11 modules wide and made of three bars and three spaces, each 1 to 4 modules wide. A symbol has five parts:
The same data can be encoded with different combinations of start, code set and shift characters, and encoders pick the shortest. A long number in Code Set C takes about half the space it would in Code Set B.
The same bar patterns mean different characters depending on the active code set. GS1-128 is Code 128 with a fixed data structure.
| Variant | What it encodes | Typical use |
|---|---|---|
| Code Set A | Uppercase letters, digits, punctuation and ASCII control characters (NUL to US) | Data that includes ASCII control characters |
| Code Set B | Uppercase and lowercase letters, digits and punctuation (printable ASCII to DEL) | Mixed-case text, URLs and alphanumeric IDs |
| Code Set C | Pairs of digits, 00 to 99, one pair per character | Long numbers such as serial, order and shipment numbers |
| Extended characters | Byte values 128 to 255, through the FNC4 character | Characters outside the ASCII range |
| GS1-128 | Code 128 with FNC1 after the start character and GS1 Application Identifiers for data such as the SSCC, GTIN, batch or lot and expiration date. Up to 48 data characters. Formerly UCC-128. | GS1 logistic labels on cases and pallets. Parse it with the GS1 parser |
Code 128 is the general-purpose linear code for identifiers that need letters, mixed case or long numbers.
GS1-128 carries the SSCC that identifies each case or pallet on a GS1 logistic label, often with GTIN, batch and dates. FedEx packages, for example, carry Code 128 and PDF417.
Barcode scanning for logistics →Warehouses scan Code 128 labels at receiving, storage and dispatch, because the code fits detailed product and location data on a small label and its check character catches misreads.
Barcode scanning for warehousing →Part numbers on parts packaging are encoded in Code 128 or Data Matrix, and Code 128 is widely used to encode vehicle identification numbers. It holds a 17-character VIN in less space than Code 39.
Barcode scanning for automotive →Hospitals use Code 128 for medication labeling, patient identification and inventory management.
Barcode scanning for healthcare →The barKoder Barcode Scanner SDK reads Code 128 on iOS, Android, the web, Windows and Linux, and in Flutter, React Native, .NET MAUI, Capacitor, Cordova and NativeScript apps. These features matter most for this code.
Reads 1D barcodes deformed along the Z axis, where no straight line crosses all the bars: labels on bottles, tubes and other curved or uneven surfaces. It is off by default and enabled in the SDK settings.
Segment Decoding® →VIN mode enables Code 128 together with Code 39, Data Matrix and QR Code, with settings tuned for 17-character VINs. Segment Decoding also reads highly distorted Code 128 VINs.
VIN Scanner SDK →Turns the GS1-128 string into labeled fields such as SSCC, GTIN, batch and expiry. It handles fixed- and variable-length Application Identifiers and follows the GS1 General Specifications.
GS1 Barcode Parser →Decodes several barcodes in a single camera view, whatever their type or size. Use it to capture all the Code 128 labels on a pallet or shelf in one pass.
Batch MultiScan →Enable only the decoders you need. These lines from the barKoder Flutter general example enable Code 128, Code 39 and EAN-13.
// Enable the barcode types and add others if you need
_barkoder!.setBarcodeTypeEnabled(BarcodeType.code128, true);
In the Web SDK the decoder is Barkoder.constants.Decoders.Code128. Its configuration also takes a minimum and maximum length, so you can ignore codes that don't match your label format.
General examples for other platforms: Web SDK, Android, iOS, React Native, Capacitor, Cordova, .NET MAUI and NativeScript. VIN mode with Code 128: Web SDK VIN example.
Install the free barKoder demo app, or open the web demo, and scan your own shipping, warehouse and parts labels before you integrate the SDK.
iPhone and iPad
Scan with your camera, or point it at the QR code to open the App Store.
Android phones and tablets
Scan with your camera, or point it at the QR code to open Google Play.
Any modern browser
Runs the Web SDK in your browser, on desktop or mobile, with nothing to install.
Test with known samples. Print or display the testing sheet and scan each 1D and 2D barcode with the demo app. The data sheet summarizes the SDK for your team.
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Code 128 is a linear (1D) barcode defined in ISO/IEC 15417. It encodes all 128 ASCII characters, has variable length and ends with a mandatory check character. Its three code sets let it encode mixed-case text or pack two digits into each character, so it fits more data on a label than older codes such as Code 39. It is used on shipping labels, warehouse and parts labels, VINs and hospital labels.
GS1-128 is Code 128 used under GS1 rules. The symbol starts with the FNC1 character and carries GS1 Application Identifiers, such as the SSCC, GTIN, batch or lot and expiration date, in up to 48 data characters. Any Code 128 reader decodes it; to get the fields, pass the result to the GS1 parser, which returns them labeled instead of as one string.
They are the three code sets. Code Set A covers uppercase letters, digits, punctuation and ASCII control characters. Code Set B covers uppercase and lowercase letters, digits and punctuation. Code Set C encodes pairs of digits from 00 to 99. A symbol can switch sets as it goes, and the reader decodes them all, so you don't choose a set when scanning. "Barcode 128C" usually means a symbol encoded mostly in Code Set C.
The one that reads your real labels on your target devices. Test SDKs on wrinkled, curved and poorly printed labels, check that they parse GS1-128 and run on your platforms. barKoder reads deformed Code 128 with Segment Decoding®, parses GS1-128 with the GS1 parser, and runs on iOS, Android, the web and frameworks such as Flutter, React Native and .NET MAUI. The free trial runs for 30 days on up to 25 devices.
For most new labels, yes. Code 128 has higher data density, so the same data fits in less space. It has a built-in check character, which is optional in Code 39, and it encodes all 128 ASCII characters, while standard Code 39 covers uppercase letters, digits and a few special characters. Code 39 is still common on older labels and VINs, and barKoder reads both. See Code 39.
Yes. To check a single label, scan it with your camera or upload a photo or screenshot to the free online barcode scanner. To decode Code 128 inside your own web app, use the WASM Barcode Scanner SDK, which reads from the camera or from image files.
Test the SDK on your own shipping, warehouse and parts labels with a free 30-day trial, or talk to an SDK expert about your project.
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