SSCC-18 & GTIN check digit calculator
Paste a full code to validate it, or the first 17 digits (SSCC) / body of a GTIN to compute the check digit. GS1 mod-10, computed in your browser.
🔒 Runs entirely in your browser
How the GS1 mod-10 check digit works
From the rightmost digit of the body, multiply digits alternately by 3 and 1, sum the products, and the check digit is what brings the sum up to the next multiple of 10:
Body: 0 0 8 1 2 3 4 5 6 0 0 0 0 0 0 0 1 1 (17 digits of an SSCC) Weights: 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 (3 on the rightmost) Sum of products = 73 → next multiple of 10 = 80 → check digit = 7
What an SSCC-18 is made of
| Part | Digits | Meaning |
|---|---|---|
| Extension digit | 1 | Yours to assign (often package-type or just 0) |
| GS1 company prefix | 7–10 | Assigned to your company by GS1 — the same prefix as your UPCs |
| Serial reference | fills to 17 | Your sequential carton/pallet number — never reuse within retention windows |
| Check digit | 1 | Computed (above), never chosen |
Why check digits matter in retail EDI
The SSCC on your carton label must match the MAN segment of your 856 ASN exactly — and receiving systems recompute the check digit on scan. Invalid or mismatched SSCCs are a top-5 cause ofASN chargebacks. The most common corruption source isn't typos — it's Excel mangling long numbers into scientific notation.
Generating ASNs by hand? FluentEDI builds the 856 — SSCCs validated, hierarchy correct — from your shipment spreadsheet.Join the waitlist →