Invalid Value [gtin] in Merchant Center: How to Fix It

What this issue means

Google validates every GTIN you submit. According to its product data specification, a valid GTIN:

• Contains only digits (spaces and dashes are accepted but ignored)
• Is 8, 12, 13 or 14 digits long (UPC is 12, EAN and ISBN-13 are 13, JAN is 8 or 13, ITF-14 is 14)
• Ends with a correct check digit calculated using the GS1 standard

If any of these fail, Merchant Center flags the value as invalid. Depending on the product, this can disapprove the item or limit its performance, because Google can no longer match it to the right catalog product.

Why it happens

These are the causes we see most often in real feeds:

• Leading zeros dropped. A UPC like 012345678905 becomes 12345678905 (11 digits) after a CSV passes through Excel or Google Sheets. Eleven digits is not a valid length.
• Scientific notation. Spreadsheets display long numbers as 8.85909E+11, and if the file is saved that way, the feed sends the literal text.
• Typos and transposed digits. One wrong digit almost always breaks the check digit.
• SKUs or internal codes in the barcode field. Values like TSHIRT-RED-M or a 6-digit warehouse number aren't GTINs.
• Placeholder values. Some stores fill the barcode with 0, 000000000000, N/A or 1234567890123 to "satisfy" a required field.
• ISBN-10 or UPC-E submitted as is. Google asks you to convert ISBN-10 to ISBN-13 and 8-digit UPC-E codes to their 12-digit UPC-A form.
• Multiple values in one field. Two barcodes pasted with a comma into a single Shopify barcode field.

How to fix it

1. Pull the list. In Merchant Center, open Products > Needs attention, filter for "Invalid value [gtin]", and download the CSV. Compare the submitted GTINs against your source data.

2. Diagnose each value. Look at the length first. Eleven digits usually means a missing leading zero; add it back. Then verify the check digit. You can do this manually:

   • Take all digits except the last one.
   • Starting from the rightmost of those digits, multiply alternately by 3 and 1.
   • Add the results. The check digit is the number you'd add to reach the next multiple of 10 (or 0 if the sum is already a multiple of 10).
   • If that doesn't match the last digit, the code is wrong.

   Our free GTIN checker runs this calculation for you, which is much faster for a whole list.

3. Get the correct number. For values that fail the check digit, don't guess. Scan the physical barcode, check the manufacturer's spec sheet, or request a barcode file from your supplier.

4. Correct the data at the source:

   • Shopify (Google & YouTube app): Edit the variant's Barcode field. If you bulk-edit through CSV, format the Variant Barcode column as Text before pasting, or import using a tool that preserves text formatting. Changes sync to Merchant Center automatically.
   • WooCommerce: Update the GTIN field your feed plugin maps (the core GTIN/UPC/EAN/ISBN field on the Inventory tab, or the Google for WooCommerce product attribute). For variable products, check each variation.
   • Feed files and supplemental sources: Fix the gtin column, save as UTF-8 text, and re-upload. If one source sends bad values you can't edit, a supplemental source keyed on id can override gtin with the correct number.

5. Remove what can't be fixed. If a product doesn't have a GTIN, delete the value rather than leaving a placeholder. Then submit brand and mpn, or identifier_exists set to no for custom items.

6. Fix one product quickly in Merchant Center (optional). You can open the product from Needs attention, choose Edit product, and correct the GTIN. Be aware that if your store app syncs the old value again, it will overwrite your manual edit, so always fix the source too.

How long until it's fixed

Google states that changes may take 24 to 72 hours to show on the Needs attention page. Store apps generally push corrected barcodes within hours, so most fixes clear within about three days. If a product still shows the error, check the product details in Merchant Center to see which GTIN Google actually received.

How to prevent it

• Store barcodes as text in every spreadsheet, PIM and import template.
• Validate check digits before importing new supplier catalogs, not after Google flags them.
• Never use filler values in barcode fields; leave them empty if there's no GTIN.
• Keep one GTIN per variant, and don't paste multiple codes into one field.
• After any bulk product import, spot-check 10 to 20 products in Merchant Center within a day or two.

Our guide to product feed optimization covers more ways to keep identifier data clean at scale. If you're facing hundreds of invalid barcodes from a supplier feed, Mercantads can clean, validate and correct your identifiers as part of our Merchant Center service.