How to Check Who Owns a UPC and Prove a Barcode Is Yours

Step 1: Check the check digit

First make sure the number is well formed. The last digit of every UPC and EAN is a check digit calculated from the others, so most typos break it. Paste the full number into the check digit calculator and, for a 12-digit UPC, read the line for a complete GTIN-12.

Take 614141234561, an example GTIN-12 that GS1 uses on its own website. Its check digit is correct. Mistype one digit, as in 614141284561, and the calculator reports that the check digit should be 6, not 1. GS1 US warns that adding or removing digits can land you on another company's number (GS1 US FAQ).

A correct check digit proves only that the number is well formed, not who owns it.

Step 2: Look the number up in Verified by GS1

Verified by GS1 is GS1's public lookup for barcode numbers (GTIN, UPC, EAN), locations (GLN), companies and other GS1 keys. Type the digits printed under the barcode into the product search; the page offers 9506000140445 as an example. As of October 2026, GS1's help center says the free service allows 30 queries a day, with more advanced access through your local GS1 office (GS1 support). GS1's old GEPIR search address now redirects here.

Reading the result

GS1 describes two kinds of information (What information is available in Verified by GS1?):

• Company data. For almost all GTINs, the result names the company, organization or person the number is licensed to, with license details such as the country where it was issued.
• Product data. If the brand owner has registered the product, you also see basics such as brand name, description, category, an image link, net content and country of sale.

The company named is the licensee, which isn't necessarily the brand name printed on the package. GS1 notes it may even be a company that made the product years ago (Verified by GS1). Company data without product data still tells you who licensed the number, even though that item's details aren't in the registry.

Treat product data as the brand owner's own description. GS1 US calls the check a limited automated one, confirming the GTIN is properly built and tied to a licensed prefix, and says it hasn't verified the accuracy of the brand attributes (GS1 US).

When the number isn't found

If the number isn't a GS1 GTIN or isn't in the GS1 database, Verified by GS1 shows a message with a brief explanation. Common reasons:

• A typo. Compare your digits with the package and repeat step 1.
• A number GS1 never issued, such as an internal code or a made-up number.
• A lapsed license. GS1 US says that when a prefix license expires, the company drops out of the GS1 Company Database and customers can no longer verify its UPCs (GS1 US FAQ).

A phone scanning app is no substitute: GS1 US notes that UPC numbers aren't automatically linked to barcode-scanning apps, and it doesn't provide one.

Step 3: Check a supplier's or reseller's numbers before you buy

Run the same lookup before you pay. What you should see depends on what you're buying:

• Finished products from another brand. These keep the GTIN their brand owner assigned, as explained in how to get UPC barcodes. Look up a few numbers from the supplier's samples or price list. The licensee should be that brand or a company clearly connected to it; anything else is a question for the supplier before you order.
• Numbers for your own brand. If a factory or a UPC seller offers barcodes for products sold under your brand, ask for one of the actual numbers and look it up. It will show whoever licensed the prefix, not you. GS1 US says its identifiers are for the sole use of the member they're licensed to, can't be sold on their own, and are transferred only in limited circumstances, generally a merger, acquisition or sale of a business line (GS1 US FAQ).

According to GS1 US, marketplaces check UPC numbers in the GS1 database to confirm the product is linked to your brand, and a mismatch can mean account suspension or relabeling (GS1 US). Verified by GS1's Find company search, by company name and country, shows whether the business you're dealing with turns up in GS1's registry under its own name.

Step 4: Prove the numbers are yours

When a marketplace, retailer or buyer asks, these show a number belongs to you:

1. Your GS1 US certificate. Whether you licensed a GS1 Company Prefix, a single GS1 US GTIN or a GLN, you can download your certificate from your account (GS1 US FAQ).
2. A lookup that names your company. Search your own numbers in Verified by GS1 the way a buyer would, and keep a copy of the result.
3. An active license. Per the same FAQ, letting a prefix license expire ends your authorization to use UPCs built from it.
4. A complete product record. A GS1 US prefix or GTIN comes with a free single-user GS1 US Data Hub subscription, and Data Hub powers Verified by GS1 in the U.S. Fill in the seven core attributes GS1 US asks for, including brand name and country of sale (Verified by GS1 for Brand Owners).
5. One brand name everywhere. GS1 US lists a brand name on Amazon that doesn't match the one registered with GS1 as a common cause of GTIN mismatches. If your company's legal name changes, GS1 US asks you to report it so your identifiers stay properly registered (GS1 US FAQ).

As of October 2026, GS1 US says sellers fixing an Amazon mismatch typically confirm the GTIN is licensed to them and provide GS1 documentation, such as a certificate, if Amazon asks (GS1 US).

If your number turns up where it shouldn't

Someone else's product carries your number

First make sure it's a real conflict. Anyone reselling your product must use the GTIN you assigned, according to GS1. The problem is a different product carrying your number. Then:

1. Check your own records to confirm which product you assigned that number to.
2. Gather your certificate, a saved lookup naming your company, photos of your package and barcode, and screenshots of the other listing.
3. Report it through the marketplace's or retailer's seller support, with that evidence attached.
4. Ask GS1 US Member Support for help if the registry itself looks wrong.

You find out you bought resold numbers

If a lookup shows your numbers are licensed to another company, the seller can't make them yours, for the reasons in step 3. License your own numbers from GS1 US, give each product a new GTIN, and update your packaging, labels, listings and retailer forms. For Amazon listings, GS1 US suggests asking Seller Support what steps are needed to move a listing from the old GTIN to a new GS1-issued one without losing its reviews and sales history.

ISBNs and internal codes

ISBNs

Books use ISBNs from national ISBN agencies. Bowker is the official U.S. agency and also runs Books In Print, a bibliographic database for publishers, retailers and libraries built from publisher-supplied data (Bowker). To see who an ISBN belongs to, search the International ISBN Agency's Global Register of Publishers by ISBN prefix, complete ISBN or publisher name; simple searches need no login.

To be identified as the publisher, the ISBN has to be your own. Bowker's FAQ says ISBNs can't be transferred one at a time, a printer or publishing services company can't sell or give you one of its ISBNs, and you can't use a friend's. The barcode side is covered in ISBN barcodes for books.

Internal codes

SKUs, bin labels and asset tags have no outside registry, so you are the registry. Keep one master list of every code, what it's assigned to and when, and don't reuse retired codes. The SKU generator flags SKUs that come out identical, and the label sheet tool warns when a value appears more than once on the sheet you're printing. Both check only the list in front of them, so also compare new codes with your master list.

Next step

Pick one product, confirm its UPC with the check digit calculator, then look it up in Verified by GS1 and save the result next to your GS1 US certificate. If the company named isn't yours, follow the resold-numbers steps above before you print another run of packaging.