GS1-128

Updated: April 22, 2026

Does IronBarcode Support GS1 UCC/EAN-128 Symbology?

Barcodes with GS1 are recognized and decoded accurately. However, the issue lies in the current lack of brackets in the displayed barcode value.

When using GS1-128, IronBarcode currently outputs: 01950123456789033103000123 (which is recognized as a Code 128 barcode with GS1 signature). The desired value to be displayed on the image output would be: 01950123456789033103000123. However, the barcode scanner will output (01)95012345678903(3103)000123 with a detection of the barcode type as Code128.

For generating a GS1-128 barcode, use the following code:

using IronBarCode;

class BarcodeExample
{
    static void Main()
    {
        // Create a GS1-128 barcode using the specified value
        GeneratedBarcode barcode = BarcodeWriter.CreateBarcode("01950123456789033103000123", BarcodeWriterEncoding.Code128GS1);

        // Add the barcode value text below the barcode on the generated image
        barcode.AddBarcodeValueTextBelowBarcode();

        // Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png");
    }
}

using IronBarCode;

class BarcodeExample
{
    static void Main()
    {
        // Create a GS1-128 barcode using the specified value
        GeneratedBarcode barcode = BarcodeWriter.CreateBarcode("01950123456789033103000123", BarcodeWriterEncoding.Code128GS1);

        // Add the barcode value text below the barcode on the generated image
        barcode.AddBarcodeValueTextBelowBarcode();

        // Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png");
    }
}

Imports IronBarCode

Friend Class BarcodeExample
	Shared Sub Main()
		' Create a GS1-128 barcode using the specified value
		Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode("01950123456789033103000123", BarcodeWriterEncoding.Code128GS1)

		' Add the barcode value text below the barcode on the generated image
		barcode.AddBarcodeValueTextBelowBarcode()

		' Save the barcode image as a PNG file
		barcode.SaveAsPng("gs1code128.png")
	End Sub
End Class

Imports IronBarCode

Friend Class BarcodeExample
	Shared Sub Main()
		' Create a GS1-128 barcode using the specified value
		Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode("01950123456789033103000123", BarcodeWriterEncoding.Code128GS1)

		' Add the barcode value text below the barcode on the generated image
		barcode.AddBarcodeValueTextBelowBarcode()

		' Save the barcode image as a PNG file
		barcode.SaveAsPng("gs1code128.png")
	End Sub
End Class

Output barcode

Output barcode example

The above code generates a GS1-128 barcode with a default divider. If you want to add additional dividers, you can insert the Unicode separator \u00f1. However, note that when using the AddBarcodeValueTextBelowBarcode method, the Unicode character ñ (code 0x00F1) will be displayed. To overcome this limitation, an alternative approach is to manipulate the string and pass the modified value to the AddAnnotationTextBelowBarcode method. This way, you can achieve the desired display of the barcode value without the ñ character.

using IronBarCode;

class BarcodeExampleWithAnnotation
{
    static void Main()
    {
        // Original barcode value
        string barcodeValue = "0195012345678903310300012300\u00f10000000123300000\u00f10000012312300000";
        
        // Remove unwanted unicode characters for display purposes
        string trimmedString = barcodeValue.Replace("\u00f1", "");

        // Create a GS1-128 barcode using the original value
        GeneratedBarcode barcode = BarcodeWriter.CreateBarcode(barcodeValue, BarcodeWriterEncoding.Code128GS1);

        // Add a custom annotation text below the barcode with the trimmed value
        barcode.AddAnnotationTextBelowBarcode(trimmedString);

        // Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png");
    }
}

using IronBarCode;

class BarcodeExampleWithAnnotation
{
    static void Main()
    {
        // Original barcode value
        string barcodeValue = "0195012345678903310300012300\u00f10000000123300000\u00f10000012312300000";
        
        // Remove unwanted unicode characters for display purposes
        string trimmedString = barcodeValue.Replace("\u00f1", "");

        // Create a GS1-128 barcode using the original value
        GeneratedBarcode barcode = BarcodeWriter.CreateBarcode(barcodeValue, BarcodeWriterEncoding.Code128GS1);

        // Add a custom annotation text below the barcode with the trimmed value
        barcode.AddAnnotationTextBelowBarcode(trimmedString);

        // Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png");
    }
}

Imports IronBarCode

Class BarcodeExampleWithAnnotation
    Shared Sub Main()
        ' Original barcode value
        Dim barcodeValue As String = "0195012345678903310300012300" & ChrW(&HF1) & "000000123300000" & ChrW(&HF1) & "0000012312300000"
        
        ' Remove unwanted unicode characters for display purposes
        Dim trimmedString As String = barcodeValue.Replace(ChrW(&HF1), "")

        ' Create a GS1-128 barcode using the original value
        Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode(barcodeValue, BarcodeWriterEncoding.Code128GS1)

        ' Add a custom annotation text below the barcode with the trimmed value
        barcode.AddAnnotationTextBelowBarcode(trimmedString)

        ' Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png")
    End Sub
End Class

Imports IronBarCode

Class BarcodeExampleWithAnnotation
    Shared Sub Main()
        ' Original barcode value
        Dim barcodeValue As String = "0195012345678903310300012300" & ChrW(&HF1) & "000000123300000" & ChrW(&HF1) & "0000012312300000"
        
        ' Remove unwanted unicode characters for display purposes
        Dim trimmedString As String = barcodeValue.Replace(ChrW(&HF1), "")

        ' Create a GS1-128 barcode using the original value
        Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode(barcodeValue, BarcodeWriterEncoding.Code128GS1)

        ' Add a custom annotation text below the barcode with the trimmed value
        barcode.AddAnnotationTextBelowBarcode(trimmedString)

        ' Save the barcode image as a PNG file
        barcode.SaveAsPng("gs1code128.png")
    End Sub
End Class

Output barcode

Output barcode with annotation example

When scanning the barcode, the output will be (01)95012345678903(3103)000123(00)0000000123300000(00)00012312300000, and the barcode type will be detected as GS1Code128.

Analyze GS1-128 Encoding

IronBarcode can also analyze the physical encoding of a GS1-128 barcode, showing which Code 128 character sets (A, B, or C) are used for each segment of the data. Use the Code128GS1Parser.ParseWithEncoding method to parse a GS1 string with encoding analysis included.

using IronBarCode;

// GS1-128 with encoding analysis
var gs1Result = Code128GS1Parser.ParseWithEncoding("(01)09501101530003");
Console.WriteLine(gs1Result.CharacterSetSummary);  // "C"
Console.WriteLine(gs1Result.HasEncodingInfo);      // true

using IronBarCode;

// GS1-128 with encoding analysis
var gs1Result = Code128GS1Parser.ParseWithEncoding("(01)09501101530003");
Console.WriteLine(gs1Result.CharacterSetSummary);  // "C"
Console.WriteLine(gs1Result.HasEncodingInfo);      // true

Imports IronBarCode

' GS1-128 with encoding analysis
Dim gs1Result = Code128GS1Parser.ParseWithEncoding("(01)09501101530003")
Console.WriteLine(gs1Result.CharacterSetSummary)  ' "C"
Console.WriteLine(gs1Result.HasEncodingInfo)      ' True

Imports IronBarCode

' GS1-128 with encoding analysis
Dim gs1Result = Code128GS1Parser.ParseWithEncoding("(01)09501101530003")
Console.WriteLine(gs1Result.CharacterSetSummary)  ' "C"
Console.WriteLine(gs1Result.HasEncodingInfo)      ' True

Since GS1-128 data is primarily numeric, the encoder uses Code C for maximum compactness. The HasEncodingInfo property confirms that encoding analysis is available on the result.

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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