GS1-128 Symbol Checksum Calculator

How GS1-128 Symbol Checksum Calculator Works?

The GS1-128 Symbol Checksum Calculator works by applying the Code 128 modulus 103 rule to the full symbol, with FNC1 (value 102) in position 1 straight after the start character. GS1 data inside the symbol keeps its own GS1 Modulus 10 check digits.

1. 1Start with Start C (105) for numeric data.
2. 2Place FNC1 (102) in position 1 to mark the symbol as GS1-128.
3. 3Add the Application Identifier and data as Code C digit pairs.
4. 4Multiply each symbol value by its position and add the start value.
5. 5Take the total modulo 103 as the symbol check value.

GS1-128 Symbol Checksum Calculator Formula

The GS1-128 formula is Check = (105 + 1×102 + Σ i·vᵢ) mod 103 for a Code C symbol.

Check value = (105 + 102×1 + Σ (i + 1) × vᵢ) mod 103

• 102 is FNC1.
• vᵢ are the Code C pair values.

Values: FNC1 01 09 50 11 01 53 00 03
Weighted total = 895
895 mod 103 = 71

GS1-128 Symbol Checksum Calculator Conversion Table

The GS1-128 conversion table lists common element strings with their symbol check value.

What is GS1-128 Symbol Checksum Calculator?

A GS1-128 Symbol Checksum Calculator is a tool that computes the Code 128 symbol check value of a GS1-128 barcode. GS1-128 is Code 128 with FNC1 in the first data position.

A GS1-128 symbol carries 2 independent checks: the modulus 103 symbol check and the GS1 Modulus 10 check digit inside each GTIN or SSCC.

What are the uses of GS1-128 Symbol Checksum Calculator?

There are 3 main uses of the GS1-128 Symbol Checksum Calculator, including logistics labels, label printer testing, and scan failure analysis.

• Logistics labels: Shippers verify SSCC and GTIN symbols on pallet labels.
• Label printer testing: Engineers compare printer output with expected symbol values.
• Scan failure analysis: Quality teams check whether rejected labels carry a wrong symbol check.