Walmart GTIN / UPC / EAN Check Digit Calculator
Walmart rejects listings with an invalid GTIN check digit. Paste your number, get a verdict and the corrected barcode in seconds.
Is your GTIN / UPC / EAN valid?
GTIN-12 (UPC), GTIN-13 (EAN-13) and GTIN-14 all end in a check digit computed from the first digits: starting from the right, every second digit is multiplied by 3 and summed with the rest, then the check digit makes the total a multiple of 10. Walmart validates GTINs at listing time — an invalid check digit is one of the most common 'GTIN not valid' rejections. This calculator validates a GTIN, fixes a wrong check digit, and shows the exact math.
Validate or fix a GTIN
Result
How the GTIN check digit works
The last digit of every GTIN is calculated from the digits before it. Walmart rejects listings whose GTIN fails this check, so a bad digit blocks a listing before anything else.
The algorithm
For a GTIN-13 (EAN), take the first 12 digits. Working from the right of those 12, multiply every other digit by 3 and the rest by 1 (positions 2, 4, 6… from the left get the 3× weight). Add the products; the check digit is (10 − sum mod 10) mod 10. GTIN-12 (UPC-A) runs the same routine on 11 digits, and GTIN-14 on 13 digits.
The formula
check digit = (10 − (Σ weighted digits) mod 10) mod 10. The calculator applies the GS1 weighting to your input, tells you the digit GS1 expects, and returns the corrected full number you can paste straight into a listing.
Where the numbers come from
The algorithm is the GS1 General Specifications check-digit calculation, identical across UPC-A, EAN-13 and ITF-14. Walmart's item setup validates the check digit before a GTIN is accepted, which is why this check matters at listing time.
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Open tool ↗GTIN Check Digit
Validate a GTIN-12 (UPC), GTIN-13 (EAN) or GTIN-14 and auto-fix the check digit — free, in your browser.
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Generate a GS1 Digital Link QR for Sunrise 2027 — encodes your GTIN in a web-enabled 2D barcode.
Open tool ↗All Walmart Tools
WFS fee & profit, FBA vs WFS, claims and GTIN validation.
Open Walmart hub ↗GTIN check digit — how the math works
How the check digit works (GS1 standard): for GTIN-13, take the first 12 digits; moving right-to-left, multiply every other digit (positions 2,4,6… from the left, i.e. the even-indexed ones) by 3 and the others by 1; sum; the check digit = (10 − (sum mod 10)) mod 10. GTIN-12 (UPC-A) and GTIN-14 follow the same algorithm on 11 and 13 digits respectively. Walmart rejects listings whose GTIN fails this check — the fix is usually a single digit.
Walmart GTIN / UPC / EAN Check Digit Calculator — FAQ
What does a check digit do?
It is the last digit of a GTIN, computed from the earlier digits by the GS1 algorithm. It lets Walmart (and every scanner) catch transcription errors instantly — a wrong check digit means a different product or a rejection.
Why does Walmart say my GTIN is not valid?
The most common reason is an invalid check digit — a single typo in a 13-digit EAN. The fix is usually one digit. It can also mean the GTIN is not assigned to your company (GS1 prefix mismatch) or the category requires a different identifier.
Can I generate a GTIN myself?
No — a valid GTIN must come from a GS1-issued prefix (or a licensed reseller). This tool only validates and fixes the check digit of a number you already have; it does not create new GTINs.
Does validating the check digit guarantee Walmart accepts it?
No. It guarantees the number is algorithmically well-formed. Walmart can still reject GTINs that are unassigned, category-mismatched or already in use by another seller.
Sources & methodology
How this calculator was built and where the reference figures come from.
Last verified: August 2026 · Confidence: High
Primary source: GS1 — GTIN check digit
Reference rates are editable and drawn from public policy reports; confirm the exact figures with your Walmart seller agreement and the relevant authority before relying on them.