Do You Need a GTIN for Google Shopping? A UK Seller's Guide

Short answer: you need a GTIN for Google Shopping if the manufacturer has assigned one to the product. If you sell branded goods made by someone else, Google Merchant Center expects the correct GTIN, which is the barcode number on the packaging. Products that leave it out can be disapproved or shown less often.

If the product genuinely has no GTIN, you don't need one. That covers own-brand goods you have not registered, handmade items and one-off pieces. Tell Google honestly using the identifier_exists attribute, and give a clear brand and, where you have one, a manufacturer part number (MPN).

So the rule isn't "every product needs a barcode". The rule is "if a GTIN exists, submit it, and if it doesn't, say so properly." Small retailers often get this wrong in both directions. Some miss real GTINs. Others invent fake ones or mark everything as having no identifier. Both mistakes cost visibility, and both are easy to avoid once you understand how Google treats product identifiers.

What a GTIN actually is

GTIN stands for Global Trade Item Number. It is the number under the barcode on almost every mass-produced product, issued through GS1, the organisation that manages barcode standards worldwide. Each GTIN identifies one specific product. That means one size, one colour and one pack size from one brand.

"GTIN" is an umbrella term for several formats. Google accepts all of them in the same gtin attribute, so you don't need to label which type you are submitting.

Format	Length	Where you will usually see it
EAN (GTIN-13)	13 digits	Most products sold in the UK and Europe
UPC (GTIN-12)	12 digits	Products made for the North American market, common on US imports
EAN-8 (GTIN-8)	8 digits	Small items where a full barcode will not fit
JAN	8 or 13 digits	Products made for the Japanese market
ISBN	10 or 13 digits	Books
ITF-14 (GTIN-14)	14 digits	Outer cases and multipacks

Submit digits only, with no spaces or dashes, and keep any leading zeros. That last point matters more than it sounds. Spreadsheets like to treat GTINs as numbers and quietly strip the zero from the front, which turns a valid code into an invalid one. If you edit your feed in Excel or Google Sheets, format the GTIN column as text before you paste anything in.

A GTIN is also not the same as your SKU. Your SKU is your own internal stock code. The GTIN is a globally registered number that means the same thing to every retailer selling that item. Google uses the GTIN to work out exactly what you are selling. Your SKU tells it nothing.

When Google Merchant Center requires a GTIN

Google's policy is straightforward. For new products, a GTIN is required whenever the manufacturer has assigned one. If you resell branded products from other companies, that applies to you. Electronics, toys, beauty, kitchenware, books, tools and branded clothing almost always carry a GTIN, and Google expects to see it.

Google knows a lot about which products have GTINs. It holds a huge catalogue of products and their identifiers, and it can check the GTIN you submit against the brand you name. Every GTIN starts with a company prefix registered to a particular business. If you claim a product is from Brand A but the GTIN prefix belongs to Brand B, that inconsistency gets noticed.

What happens if you leave it out

When a GTIN is missing from a product that should have one, you will usually see one of these outcomes in Merchant Center:

• Limited performance warnings. The product stays live, but Google flags that it is missing identifiers and may show it less often.
• Disapproval. The product is blocked from Shopping ads and free listings until you fix it.
• Invalid value errors. You submitted something in the GTIN field, but it failed validation. This is usually a typo, a stripped leading zero, a SKU in the wrong field or a made-up number.

The exact wording of these diagnostics changes over time as Google updates Merchant Center. The principle doesn't change. A missing or wrong identifier on a product that has one is treated as a data quality problem, and data quality problems cost you impressions.

What about used and refurbished products?

If you sell second-hand or refurbished items, set the condition attribute to "used" or "refurbished". Google is more relaxed about identifiers here. Still, if the item originally had a GTIN (a used games console or a refurbished phone, say), submitting it helps Google match the product properly. If you have it, include it.

When you don't need a GTIN

Plenty of legitimate products never had a GTIN. Google accepts this, and you won't be penalised for being honest about it. These are the most common cases we see with small UK retailers.

Not having a GTIN doesn't stop you appearing in Google Shopping. Plenty of own-brand and handmade sellers run profitable Shopping campaigns without a single barcode. What matters is giving Google accurate information and strong titles, images and descriptions instead. Our guide on how to appear in Google Shopping covers the wider setup if you are starting from scratch.

How the identifier_exists attribute works

The identifier_exists attribute tells Google whether standard product identifiers exist for an item. It takes a simple yes or no value.

Set it to no when the product is new, has no GTIN, and you can't supply both a brand and an MPN either. That tells Google you haven't simply forgotten the identifiers. They don't exist.

If you do have a brand and an MPN, you can submit those instead, and Google will use them to understand the product. If the product has a GTIN, submit the GTIN. In that case identifier_exists should either be left out or set to yes.

The mistake that catches people out

The most damaging shortcut we see is setting identifier_exists to no across an entire feed to clear errors quickly. It looks like a fix, because the "missing GTIN" warnings disappear. But Google can still recognise branded products that have GTINs, and telling it they have no identifiers is inaccurate data. That can lead to fresh warnings, disapprovals or weaker performance, and it can make your account look careless.

Use identifier_exists only on the products that genuinely have no identifiers. If you have a mixed catalogue, with some branded stock from suppliers and some own-brand lines, set the attribute product by product, not across the board.

Worked example: an own-brand candle shop

Say you run a small online shop selling candles you make yourself under the brand "Hearth and Wick". You have never bought barcodes. For each candle, a sensible feed setup looks like this:

• brand: Hearth and Wick
• gtin: left empty
• mpn: your own product code, such as HW-AMBER-200 (because you are the manufacturer, your code is a legitimate part number)
• identifier_exists: either set to no, or left out if you are supplying brand and MPN

Either approach is acceptable. What matters is consistency and honesty. Pick one approach and apply it to every product in that range.

Worked example: a kitchenware reseller

Now say you sell branded pans, knives and utensils from well-known manufacturers. Every one of those products has a GTIN printed on the packaging and listed on your supplier's product data sheet. Here the correct setup is:

• brand: the manufacturer's brand, not your shop name
• gtin: the exact barcode number for that size and colour
• mpn: the manufacturer's part number, if you have it (optional but useful)
• identifier_exists: not needed

If you sell these products without GTINs, you are competing with your hands tied. Other retailers selling the same pan with the correct GTIN will be matched to Google's catalogue, and you may not be.

Bundles and multipacks: which GTIN to use

Bundles and multipacks cause more confusion than anything else in GTIN handling. Google treats them differently, and it has two attributes specifically for them: is_bundle and multipack.

A multipack is several of the same product sold together, such as six identical bars of soap. A bundle is a main product sold with other different items, such as a camera with a bag and a memory card.

Scenario	Attribute to use	Which GTIN to submit
Manufacturer multipack with its own barcode	None needed	The GTIN printed on the multipack
Multipack you created yourself (e.g. six single items sold together)	multipack = 6	The GTIN of the individual item
Manufacturer bundle with its own barcode	None needed	The GTIN of the bundle
Bundle you created around a main product	is_bundle = yes	The GTIN of the main product
Hamper or gift set of your own made products	is_bundle = yes	None, set identifier_exists to no if there is no brand and MPN

Why the main product's GTIN matters in a bundle

When you bundle a camera with accessories, the person searching is usually looking for the camera. Submitting the camera's GTIN with is_bundle set to yes tells Google, "this listing is that camera, plus extras". Google can then show your bundle alongside other listings for the camera while understanding that your price includes more than the camera alone. Without the is_bundle flag, your higher price could look uncompetitive against sellers offering the camera on its own.

Be sensible about what counts as the main product. It should be the item that drives the purchase and accounts for most of the value. A phone case thrown in with a phone doesn't change the fact that the phone is the main product.

Mixed gift hampers

Gift hampers are a common edge case for small UK businesses, especially around Christmas. If your hamper is built around one clearly dominant branded item (a bottle of a well-known gin, for example), use that item's GTIN with is_bundle set to yes. If it is a mix of smaller items with no obvious main product, or mostly things you have made yourself, treat it as an own-brand product: your brand name, no GTIN, and identifier_exists set to no.

Should you buy barcodes for your own products?

You don't need GTINs to sell own-brand products on Google Shopping. But there are good reasons a growing brand might register them anyway.

• Marketplaces. Some marketplaces expect barcodes for most categories, and having them makes listing much simpler.
• Retail stockists. If shops or wholesalers want to stock your products, they will almost certainly want barcodes for their tills and stock systems.
• Catalogue matching. Once registered and in use, your GTINs let Google treat your products like any other identified product, including grouping reviews from other retailers who stock them.

In the UK, the official route is membership of GS1 UK, which issues a company prefix and lets you create GTINs registered to your business. There is a joining fee and an annual fee that scales with turnover, so check their current pricing before you decide.

Be wary of very cheap barcodes sold by third-party resellers. These numbers may originally have been registered to another company. Google can check who a GTIN prefix belongs to, and if it doesn't match the brand you submit, you can end up with warnings or mismatches rather than the benefit you paid for. If you are going to register barcodes, do it properly.

And never make up a GTIN. Every GTIN has a check digit calculated from the other digits, so most invented numbers fail validation straight away. The ones that happen to pass may belong to a real product from another company, which is worse. A fake GTIN is far more harmful than an honest "no identifier".

How correct identifiers improve Shopping visibility and approvals

Getting GTINs right isn't just about clearing errors. It changes how Google understands and shows your products.

Google knows exactly what you are selling

With a valid GTIN, Google can match your listing to its own record for that product. That means it can show your ad for very specific searches, such as an exact model number, even if your title doesn't include every detail. Without a GTIN, Google relies entirely on your title, description and other attributes to guess what the product is.

Your listing can sit alongside other sellers

When several retailers sell the same identified product, Google can group them so shoppers can compare offers. If your price, delivery and returns are competitive, being part of that comparison works in your favour. If you are missing the GTIN, you may simply not appear in it.

Product ratings can carry across

Google aggregates product reviews using identifiers. A correctly identified branded product can show star ratings drawn from reviews across multiple sources, which makes the listing more eye-catching. Products without identifiers have a much harder time building up ratings.

Fewer disapprovals, healthier account

Every disapproved product is a product earning nothing. Repeated data quality problems also make a Merchant Center account harder to manage. You spend time firefighting issues instead of improving the campaigns. Clean identifiers remove one of the most common sources of warnings.

Better competitive insight

Merchant Center's price benchmarking and competitiveness features depend on matching your products to the same items sold elsewhere. If Google can't match them, you lose useful information about whether your pricing is helping or hurting your Shopping performance.

Identifiers are one part of feed quality. If you want the wider picture on titles, images, product types and campaign structure, our specialist's playbook for optimising Google Shopping goes through it in detail.

Common GTIN mistakes we see in small business feeds

After 15 years of working with small businesses, we see the same handful of issues again and again. Check your feed against this list.

1. Blanket identifier_exists set to no. Applied to the whole feed to make warnings go away, including branded products that do have GTINs.
2. SKUs in the GTIN field. Internal stock codes put in the barcode field because the field was empty. Google rejects these as invalid.
3. Stripped leading zeros. A spreadsheet has turned 0123456789012 into 123456789012, and the code no longer validates.
4. One GTIN for all variants. Each size, colour and pack size normally has its own GTIN. Using the parent product's barcode for every variant confuses Google and can lead to mismatches.
5. Your shop name as the brand on other people's products. If you resell a manufacturer's goods, the brand is the manufacturer, not you. Use your own name only for products you make or commission.
6. Invented or reused numbers. Made-up GTINs, or a single GTIN copied across unrelated products.
7. Feed apps not pulling the right field. The GTIN is stored correctly in your shop platform, but the feed app or integration is mapping a different field, or none at all.
8. Bundles without is_bundle. A bundle submitted with the main product's GTIN but no bundle flag, so the higher price looks uncompetitive against single items.

How to fix GTIN issues, step by step

If Merchant Center is flagging identifier problems, this is the order we work through them.

1. Find the affected products. In Merchant Center, open the product issues view and filter for problems relating to GTIN, brand or identifiers. Export the list so you can work through it methodically.
2. Sort them into groups. Separate branded products you resell (which need real GTINs) from own-brand, handmade and bundled items (which need the correct identifier_exists or bundle setup).
3. Source the real GTINs. Check the packaging, your supplier's product data or price lists, or ask your supplier directly. Most wholesalers can provide a spreadsheet of barcodes for their range.
4. Update the source, not just the feed. Put the GTIN into your shop platform so it flows through automatically. Shopify has a barcode field on every variant. Recent WooCommerce versions include a GTIN field, and older setups usually rely on a feed plugin. Fixing it at source stops the problem coming back on the next sync.
5. Set identifier_exists only where it belongs. Apply it to genuinely unidentified products, and make sure the brand attribute is filled in properly for those items.
6. Flag bundles and multipacks. Add is_bundle or multipack where needed, with the right GTIN as per the table above.
7. Use a supplemental feed for quick fixes. If you can't change your platform data immediately, a supplemental feed in Merchant Center can add or correct GTINs by product ID while you sort out the source.
8. Resync and monitor. Google needs to reprocess the updated products. Check back over the following days, confirm the warnings have cleared, and watch for new issues as you add products.

The final step is the one most people skip. Feeds aren't a one-off job. New products get added without barcodes, suppliers change ranges, and apps update. A quick monthly check of Merchant Center diagnostics catches problems before they cost you sales.

Does any of this change with Performance Max?

Many retailers now run their Shopping ads through Performance Max campaigns rather than Standard Shopping, or use a mix of both. The product feed is the foundation of both. Performance Max uses your feed data to decide where and when to show products across Search, Shopping, YouTube, Display and Gmail, so feed accuracy matters just as much.

If anything, clean identifiers matter more with automated campaigns. You have less manual control over which searches trigger your products, so the system relies heavily on the data you give it. Poor data means poor matching, however clever the bidding. That is why feed quality is the first thing we look at as part of any Google Ads management for an online shop.

Frequently asked questions

Can I use my SKU as a GTIN?

No. A SKU is your internal code and isn't registered with GS1. Put SKUs in the id or MPN field (MPN only if you are the manufacturer), and keep the GTIN field for real barcode numbers.

Will Google reject my products if I don't have GTINs?

Not if the products genuinely don't have them and you have set the feed up correctly. Disapprovals and limited performance warnings mostly hit products that do have a manufacturer GTIN but are submitted without it, or with an invalid one.

Does each variant need its own GTIN?

Usually, yes. Manufacturers normally assign a separate GTIN to each size, colour and pack size. Submit each variant as its own product with its own GTIN, linked by a shared item_group_id.

Do the same rules apply to free listings?

Yes. Free product listings and Shopping ads both draw on the same Merchant Center data, so identifier problems affect both.

Is it safe to set identifier_exists to no to clear warnings quickly?

Only for products that genuinely have no GTIN. Using it on branded products that do have GTINs feeds Google inaccurate data, and it often creates new problems instead of solving the old ones.

Do I need GTINs for second-hand products?

They aren't strictly required for used items, but if the product originally had a GTIN and you know it, submitting it helps Google understand exactly what you are selling.

Should I pay for barcodes just for Google Shopping?

Not usually. Own-brand products can run perfectly well on Google Shopping without GTINs. Registering barcodes with GS1 UK makes more sense when you also want to sell through marketplaces or retail stockists.