GTIN check digit validator
Paste barcodes and see which pass the character, length, check digit, range and placeholder checks. The same test the free feed check runs on each product’s gtin in a feed, for the numbers you have in front of you.
What it checks
Google’s gtin specification accepts 8, 12, 13 or 14 digits (EAN-8, UPC-A, EAN-13 or ISBN-13, ITF-14), spaces and dashes ignored, validates the check digit, and says not to submit a number in the restricted ranges (02, 04, 2) or the coupon ranges (05, 98, 99). The tool drops spaces and dashes, treats any other character as invalid, checks the length, recomputes the check digit, checks those ranges on 12- and 13-digit codes and on 14-digit codes that start with 0, read as 13 digits, and flags the placeholder patterns all zeros, one repeated digit and 1234567…. A valid 12-digit UPC is shown as the 13-digit GTIN it equals, with a leading zero.
What each result means for Merchant Center
An invalid value is disapproved as “Invalid value [gtin]”. Google’s gtin page says products with a missing GTIN may have limited visibility and that a product that has a GTIN assigned and is submitted without it could be disapproved; it also says “When in doubt don’t provide a GTIN”. The missing-GTIN guide covers where to find real barcodes and what to do for products that have none.
Questions merchants ask
How is the check digit calculated?
From the right, the payload digits are weighted 3, 1, 3, 1 and so on, summed, and the check digit is whatever brings the total to a multiple of ten. The tool computes it and compares; a single typo anywhere in the number fails it.
My 11-digit UPC fails. Why?
A UPC-A has twelve digits. Spreadsheets drop a leading zero when they treat the column as a number, and 012345678905 becomes 12345678905, which is no GTIN length at all. Restore the zero.
Why does a valid-looking number show as a placeholder?
Patterns such as all zeros, one repeated digit or 1234567… can pass the check digit. Google’s gtin page says not to guess or make up a value, and the free check treats them as missing. Leave the field empty instead.
Is this the same check Google runs?
Google’s gtin page asks for a correct length and check digit and no number in the restricted or coupon ranges; this tool checks the length and check digit, and the ranges on 12- and 13-digit codes and on 14-digit codes that start with 0. Google reports a valid but wrong GTIN, for example one re-used from another product, as “Incorrect GTIN”; this tool cannot see that.
Sources
Google Merchant Center Help, GTIN [gtin], How to fix: Invalid value [gtin], How to fix: Incorrect GTIN and About unique product identifiers; GS1, Global Trade Item Number.