E-commerce
GTIN Check Digit Validator
Paste barcode numbers and see which ones have a correct GS1 check digit, which do not, and what the last digit should be.
Runs in your browser; nothing is uploaded. · Free, no account · 2 min
Spaces and hyphens are ignored.
Importing a saved run into your account is coming soon. Until then, your last runs stay in this browser only, and you can download your files.
How to use
- Paste one number per line. Spaces and hyphens are ignored.
- Choose to check numbers that already have a check digit, or to add the check digit to numbers that lack one.
- Read the table: each number gets its type and a result.
- Fix the numbers in the error list, then copy the completed numbers if you used the add mode.
What it checks and how it works
A GTIN is 8, 12, 13 or 14 digits long. The last digit is a check digit. GS1 calculates it from the digits before it: from the right, multiply them by 3, 1, 3, 1 and so on, add the products, and the check digit is what brings the sum up to the next multiple of 10 (GS1 General Specifications). A number whose last digit differs from that result has a typing error.
Google's Merchant Center specification, opened on 29 Oct 2026, also excludes GTINs that start with 02, 04 or 2 (restricted for internal use) and 98 or 99 (coupons), and treats the 10-digit ISBN as deprecated in favour of the 13-digit form. The tool flags these and, for a valid ISBN-10, shows the ISBN-13.
A correct check digit shows the number is well formed. It does not show that GS1 assigned it to your product; only your GS1 member organisation can confirm that.
Sources
- GS1 General Specifications (check digit calculation, GTIN formats) opened 29 Oct 2026
- Google Merchant Center Help: Product data specification opened 29 Oct 2026
Related tools
Merchant Center Product Feed Checker
Paste your product feed and find the missing attributes, wrong values and malformed prices before Merchant Center does.
Barcode Generator
Type a product number or SKU and get a barcode you can download as SVG or PNG, with the GS1 check digit handled for you.
Product Title Builder
Fill in the product details, pick a pattern, and get a clear title that follows Merchant Center's title guidance.
Questions
About this tool
No. The check digit catches typing mistakes only. Retail GTINs are issued by GS1 member organisations, and a well-formed number can still belong to someone else or to nobody.
8 digits (GTIN-8), 12 (UPC-A, GTIN-12), 13 (EAN-13, GTIN-13) and 14 (GTIN-14). In add mode, paste the number without its last digit: 7, 11, 12 or 13 digits.
Google's specification says the ISBN-10 is deprecated and should be converted to the 13-digit ISBN. The tool shows the ISBN-13 for any valid ISBN-10 you paste.
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