GS1-128 SSCC Shipping Labels: Build the Number and the Label

What an SSCC is and who assigns it

GS1 uses the SSCC (Serial Shipping Container Code) to identify a logistic unit: any combination of items packed together for transport or storage, such as a case, pallet or parcel (GS1). It identifies one physical unit, not a product, so two identical pallets get two different SSCCs.

The GS1 General Specifications (section 4.3) set the ground rules:

• The company that physically builds the logistic unit, or the brand owner of it, assigns the SSCC.
• The number stays the same for the life of that unit.
• An SSCC must not be reassigned within one year of the date it was shipped to a trading partner, and regulations or industry rules can extend that period.

As of October 2026, GS1 US states on its barcode types page that GS1-128 barcodes can only be created with a GS1 Company Prefix. That prefix is what makes each SSCC unique worldwide. This is general information, not legal advice about number licensing.

Build the SSCC in four steps

An SSCC always has 18 digits in four parts. Your prefix length decides how many digits are left for the serial reference.

1. Pick an extension digit. GS1 says it runs from 0 to 9, is assigned by the company that builds the SSCC, and is used to add capacity to the serial reference. Starting with 0 is fine.
2. Write your GS1 Company Prefix. This example uses 0614141, GS1's own example prefix. If your GS1 US paperwork shows a U.P.C. Company Prefix such as 614141, the General Specifications say that adding a leading zero turns it into the GS1 Company Prefix you use for SSCCs.
3. Add a serial reference that brings the total to 17 digits. With a 7-digit prefix, that's 9 digits. GS1 leaves the structure to you, so a zero-padded counter works: 000000123 for your 123rd unit.
4. Calculate the check digit. Multiply the 17 digits by 3, 1, 3, 1 and so on, starting with 3 on the rightmost digit (with 17 digits, the leftmost also gets 3). For 0 0 6 1 4 1 4 1 0 0 0 0 0 0 1 2 3, the products are 0, 0, 18, 1, 12, 1, 12, 1, 0, 0, 0, 0, 0, 0, 3, 2 and 9, which total 59. The next multiple of ten is 60, so the check digit is 1.

The finished SSCC is 006141410000001231, written on the label as (00)006141410000001231. You can confirm any SSCC in the check digit calculator, which handles 18-digit SSCCs.

What goes on a GS1 logistic label

The General Specifications (section 6.6) make the SSCC the only mandatory element of a GS1 logistic label; anything else must follow GS1's Application Identifier rules.

Three building blocks

• Top block: free-format text and graphics, such as addresses or a logo. Text must be at least 3 mm high.
• Middle block: the barcode data as text with data titles such as SSCC or COUNT, ideally at least 7 mm high, with titles in English unless the partners agree otherwise.
• Bottom block: the barcodes with their human-readable lines. This is the only required block.

A label can be split into carrier, customer and supplier segments, usually in that order from the top, but the GS1-128 carrying the SSCC always goes lowest, with its bars vertical. GS1 suggests an A6 (105 × 148 mm) or 4 × 6 in. label for an SSCC with limited extra data, and A5 or 6 × 8 in. for more.

Common Application Identifiers

Three rules trip people up. AI (02) may only appear together with (00) and (37), and only when the unit isn't itself a trade item and every item at its top level shares one GTIN. AI (01) and AI (02) must never appear on the same logistic label, according to the GS1 Logistic Label Guideline. And lot numbers and dates describe the GTIN shown on the label, so a mixed pallet should carry no product data on its label at all.

Worked example: a pallet of 40 cases

Say a pallet holds 40 identical cases of GTIN-14 10614141123459, the case number built in the ITF-14 guide, all from lot LOT42 with an expiration date of December 31, 2027. The bottom block gets two GS1-128 barcodes:

1. Upper: (02)10614141123459(17)271231(37)40(10)LOT42
2. Lowest: (00)006141410000001231

Why two? A GS1-128 holds at most 48 data characters, counting AIs and FNC1 separators, and all five fields come to 20 + 16 + 8 + 4 + 1 + 7 = 56. Order matters too: (02) and (17) have a predefined length and go first, (37) is variable-length and needs an FNC1 separator after it, and (10) goes last so it needs none.

Size and placement

GS1 symbol specification table 5, for logistic units, allows a GS1-128 X-dimension (the narrowest bar) from 0.495 mm to 0.940 mm, a bar height of at least 31.75 mm (1.25 in.), quiet zones of 10X on each side, and a minimum print quality grade of 1.5/10/660. At 0.495 mm, the SSCC barcode above is about 77 mm wide, or about 87 mm (3.4 in.) with its quiet zones, which fits across a 4 in. label.

Placement rules from section 6.7:

• Pallets: put every barcode between 400 and 800 mm (16 and 32 in.) above the pallet base, and keep the barcode, including its quiet zones, at least 50 mm (2 in.) from any vertical edge. GS1 recommends two identical labels on adjacent sides, one on a short side and one on the side to its right.
• Cartons: aim for the bottom of the barcode 32 mm (1.25 in.) above the base and at least 19 mm (0.75 in.) from vertical edges.
• Nested units: when cases with their own SSCCs go onto a pallet, only the pallet's barcode should be readable, so cover the inner labels.

Every SSCC is unique, so these labels are printed one at a time as units ship. See label printers and labels for direct thermal versus thermal transfer.

Where the ASN fits

The SSCC links the physical unit to the data you send electronically in a despatch advice, also called an advance ship notice (ASN). The GS1 Logistic Label Guideline describes how they work together:

• Send the ASN when the goods are staged or loaded, so it matches what actually ships.
• List each logistic unit's SSCC and the trade items it contains, with lot and date data that match the goods.
• The receiver processes the ASN before the goods arrive. A scanned SSCC should match it, and the received quantity is added to stock automatically; depending on the agreement, the receiver may accept the unit on that scan alone.

Mixed pallets depend on the ASN, because their contents can't go on the label. Create the SSCC, the label and the ASN line from one record instead of retyping the number. GS1 US notes that you and your trading partners decide what information to share, so your customer's routing guide has the final word on which AIs it wants.

Make it with the generator

Open the barcode generator, choose GS1-128, and type the data with AIs in parentheses, such as (00)006141410000001231. It checks the length of fixed-length fields and the check digit in (00), (01) and (02), and inserts FNC1 separators where needed. Type predefined-length AIs first, because it keeps the order you enter.

It starts at GS1's 0.495 mm X-dimension and 31.75 mm bar height; keep X at or below 0.940 mm for SSCC labels. Download a PNG for your printer's dpi or an SVG at physical size and place it in your label layout. The generator doesn't check AI combination rules, lay out the whole label, assign SSCCs or grade print quality.

Next step

Find your GS1 Company Prefix, pick a numbering scheme (extension digit 0 plus a counter is enough), and calculate your first SSCC in the check digit calculator. Then print a test label, scan it, and check it against your customer's routing guide before the first shipment.