Every carton you ship to a retailer needs its own 18-digit SSCC, printed as a GS1-128 barcode and matched exactly in your 856. Here is how the number is built, what goes on the label, and a free calculator to create and check SSCCs.
An SSCC, or Serial Shipping Container Code, is an 18-digit number that identifies one shipping unit, a single carton or a whole pallet, from your dock to the retailer's receiving door. GS1 calls it the shipment's license plate. No two cartons should ever carry the same SSCC.
The SSCC is the number. GS1-128 is the barcode it is printed in, and the carton label is what carries both. Retailers, 3PLs and EDI providers use these terms loosely, which is where a lot of label confusion starts.
| Term | What it means |
|---|---|
| SSCC (SSCC-18) | The 18-digit number for one carton or pallet. Never shared, and never reused inside a year. |
| GS1-128 | The barcode type. A version of Code 128 that starts with a special FNC1 character so the scanner knows GS1 data follows. |
| UCC-128 | The old name for GS1-128, from when the Uniform Code Council ran barcodes in the US. Same barcode. |
| AI (00) | The application identifier printed in front of the SSCC. It tells the scanner an SSCC follows, so the barcode holds 20 digits in total. |
| GS1 logistic label | The whole carton or pallet label: addresses, carrier and order data, and the SSCC barcode at the bottom. US retailers usually call it the UCC-128 label. |
Every SSCC has four parts. Your GS1 Company Prefix and the serial number always add up to 16 digits, so a longer prefix leaves fewer digits for serials.
| Part | Digits | What it is |
|---|---|---|
| Extension digit | 1 | 0 to 9, chosen by you. It adds capacity and carries no other meaning. Some brands give each warehouse or label printer its own digit so their numbers can never collide. |
| GS1 Company Prefix | 4 to 12 | Your company's number from GS1, printed on your prefix certificate. If you already make UPCs from a GS1 prefix, the same prefix works for SSCCs. |
| Serial reference | 16 minus the prefix length | Your running carton number. A 7-digit prefix leaves 9 digits for serials, a 10-digit prefix leaves 6. |
| Check digit | 1 | Calculated from the first 17 digits so a scanner can catch a misread. |
Using the example prefix GS1 uses in its own documentation, 0614141, with extension digit 0 and serial 123456789 gives the SSCC 006141411234567890. Under the barcode it prints as (00) 0 0614141 123456789 0. According to GS1 US, a 7-digit prefix supports up to 10 billion SSCCs and a 9-digit prefix up to 100 million.
Create a batch of SSCCs with correct check digits, or paste one in to check it. It runs entirely in your browser, so nothing you type is sent anywhere.
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A correct check digit does not make a number unique. Keep one record of the last serial used for each prefix and extension digit, and never let two systems count from the same range.
GS1 uses the same method for SSCCs, UPCs and other GTINs. Here it is with 0 0614141 123456789 as the first 17 digits.
Everything except the check digit: 0 0614141 123456789.
Multiply the rightmost digit by 3, the next one by 1, and keep alternating all the way to the left.
For this example the total is 140.
The check digit is whatever takes the total to the next multiple of 10. 140 already is one, so the check digit is 0. A total of 137 would give 3.
GS1 sets the barcode rules but not a single fixed layout. Most US retailers use zones lettered A to I on a 4 by 6 inch label, and each retailer's routing guide decides which zones are required and what goes in them.
| Zone | What it holds | Required? |
|---|---|---|
| A. Ship from | Your company name and address | Most shipments |
| B. Ship to | The retailer's distribution center or store address | Most shipments |
| C. Carrier routing | The ship-to ZIP code as a GS1-128 barcode with AI (420), or a PRO number barcode | When the retailer or carrier asks |
| D. Carrier | Carrier name, SCAC, PRO number and bill of lading number | When the retailer or carrier asks |
| E and F. Trading partner data | Whatever the retailer specifies, such as PO number, department, style, UPC or carton 3 of 6 | Set by each retailer |
| G. Final destination barcode | The mark-for store number as a barcode | Store-level shipments |
| H. Final destination | The mark-for store name and number in text | Store-level shipments |
| I. SSCC | The SSCC as a GS1-128 barcode with AI (00), always the bottom barcode | Always |
Each retailer's routing guide has the final word. Our retailer compliance directory links to the vendor portals where those guides live.
The label says which carton this is. The EDI 856 advance ship notice says what is inside it. At the carton level of the 856, the MAN segment with the qualifier GM carries that carton's SSCC. When the retailer scans the label at receiving, it looks the SSCC up in your 856. If it is not there, or the contents do not match, the carton goes to manual receiving and the retailer bills you for the work.
In a pick-and-pack 856, every carton has its own SSCC. In a standard-pack 856, the SSCC can sit at the pallet level with the cartons underneath. Some retailers want the 18-digit SSCC in the MAN segment and others want all 20 digits with the 00 in front, so check the retailer's 856 specification before the first shipment.
Our retailer chargebacks guide covers how to dispute these deductions and stop them coming back.
You need a GS1 Company Prefix. GS1 US says brands that bought only single GS1 US GTINs have to license a prefix to create SSCCs. If you already make UPCs from a prefix, the same one works.
In practice your ERP, EDI provider or 3PL generates the numbers and prints the labels, and GS1 US notes that logistics providers assign SSCCs for their customers. The rule that prevents most duplicate-label problems is simple: one system owns the counter for each prefix and extension digit. If your own warehouse and your 3PL both print labels, give each one its own extension digit.
GS1 allows it one year after the number was created and last used. Some retailers ask for longer, and a 7-digit prefix gives you a billion serials per extension digit, so most brands never need to reuse one.
No. A UPC identifies a product and is the same on every unit of that style, color and size. An SSCC identifies one physical carton or pallet and is never shared with another.
Only the name. UCC-128 dates from when the Uniform Code Council managed barcodes in the US. That organization is now GS1 US, and the barcode is called GS1-128.
Treat a repacked carton as a new carton: new SSCC, new label and an updated 856. Shipping a repacked carton under its old label is one of the most common causes of ASN mismatches.
You can calculate the numbers in a spreadsheet, the same way the calculator above does. Printing the barcode is harder: a valid GS1-128 needs the FNC1 start character and a Code 128 check character, which a plain barcode font will not add for you. Use label software, your ERP or EDI provider, and test-scan every new label format before it ships.
The carton-by-carton document every label has to match, including pick-and-pack and standard-pack structures.
Read the guideWhere label and ASN deductions come from, the evidence that wins disputes, and how to stop repeats.
Read the guideVendor portals and routing guides for the major US department stores and big-box retailers.
Read the guideWe find where cartons, labels and the 856 drift apart, usually between the packing table and the system, and fix it at the source. If your labels are already clean, we will tell you that.
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