GTIN stands for Global Trade Item Number. It is the GS1 number used to identify a trade item: a product or group of products that can be ordered, priced or invoiced. In ecommerce, it helps stores recognize the same item even when their titles and stock codes differ.
EAN and UPC are common names for GTIN formats. For a feed or a price comparison, the useful question is whether the code describes exactly what the customer will receive.
Key Takeaways
- GTINs have 8, 12, 13 or 14 digits. EAN usually refers to a GTIN-13; UPC usually refers to a GTIN-12.
- A correct check digit can catch some typing errors. It does not prove that the number belongs to the listed product.
- Keep variants, manufacturer multipacks and cases distinct. A matching number alone does not establish equal offer contents.
- Use verified identifiers in feeds. Never invent a GTIN or replace a missing one with an internal SKU.
What Does GTIN Stand For? GTIN vs EAN vs UPC
A GTIN is the number that identifies the item. A barcode is the symbol a scanner reads to capture that number. You can store a GTIN in a catalog without storing a barcode image. Two systems can share the number without scanning a package.
EAN originally stood for European Article Number. In product data, an EAN number usually means the 13-digit GTIN carried by an EAN-13 barcode. Despite its name, it is used worldwide. UPC stands for Universal Product Code and commonly means the 12-digit GTIN carried by a UPC-A barcode.
| GTIN format | Digits, including the check digit | Familiar barcode carrier | Common use |
|---|---|---|---|
| GTIN-8 | 8 | EAN-8 | Small retail items with limited label space |
| GTIN-12 | 12 | UPC-A | Retail items, especially in North America |
| GTIN-13 | 13 | EAN-13 | Retail items worldwide |
| GTIN-14 | 14 | ITF-14 or GS1-128 | Trade item groupings, such as cases |
The number’s length does not tell you how many units a package contains. A case of six items and a case of twelve can both have a GTIN-14. Read the associated product and packaging data.
Also distinguish a GTIN-14 from a shorter GTIN stored in a 14-digit field. A system may add zeros at the start of a GTIN-12 or GTIN-13 so all stored values have the same length. That padding does not create a new product or turn a single item into a case.
A retailer’s SKU is an internal stock code. An Amazon ASIN belongs to Amazon’s catalog. Keep these in separate fields; neither becomes a GTIN because it identifies a product. The ASIN guide explains the Amazon-specific distinction.
Where to find a GTIN before comparing listings
Start with the barcode on the unit being sold. Then check the manufacturer’s product data or the supplier’s catalog. Another store’s page can help you find the number. If that listing is wrong, copying its code brings the error into your own data.
When saving the number, keep enough detail to check it later:
- The complete number, including leading zeros.
- The brand, model and manufacturer part number, where available.
- The selected size, color, capacity or other variant details.
- The number of units, contents and packaging level.
- Where the number came from, such as a package label or supplier record.
Make sure the label belongs to what the customer receives. A shipping carton may show the code for a case while the shop sells one item from it. A barcode on a warehouse sticker may be an internal stock code, rather than a GTIN.
Verified by GS1 can help check who assigned a GTIN and show product details when they are available. Enter the number in the service’s product lookup and compare the result with the item in front of you. A result that names only the company is useful, but it does not prove the exact size, color or pack contents.
If the lookup gives no useful product detail, leave the match open and ask the brand owner or supplier to confirm the number. Do not fill the gap with a similar product’s code. A GTIN also does not tell you an offer’s current price, stock status or condition.
Variants, multipacks and packaging levels need separate checks
Similar titles can describe different trade items. A black shirt in medium and the same shirt in large should each carry the GTIN assigned to that size. Copying one code across every size hides the difference in your data.
Changes in declared net content also matter. A product changing from 250 mL to 300 mL needs a new GTIN under the net-content rule, even if the name and package design stay almost the same. Review the label rather than relying on the photograph’s appearance.
Check the pack as well as the item inside it. A single item, a multipack made by the manufacturer and a case of those packs can each have their own GTIN. A change in the number of items per case can require a new case GTIN. The code for the item inside can stay the same.
Example: two similar cleanser packages
Imagine two listings for a fictional product called Clearleaf Daily Cleanser. Both show the same bottle design and fragrance.
| Detail | Package A | Package B |
|---|---|---|
| Sale unit | One 250 mL bottle | Pair of 250 mL bottles packed by the manufacturer |
| Total contents | 250 mL | 500 mL across two bottles |
| GTIN to confirm | Single bottle’s GTIN | Packaged pair’s own GTIN |
| Match decision | Compare with the same single-bottle item | Compare with the same manufacturer pack |
These are made-up packages. The table describes which codes to check without inventing real product numbers.
If the pair’s listing shows only the single bottle’s number, flag the error. The title, image and code disagree about what is sold. Dividing the pair’s price by two could help compare costs per bottle. It does not make the pair the same trade item as the single bottle.
Keep a mixed bundle distinct as well. A cleanser sold with a brush contains different products; it is not a multipack of identical bottles. The bundle pricing guide covers the separate task of evaluating the set’s price. Here, the task is to establish which set an identifier describes.
Missing or invalid GTINs: find the actual error
An invalid GTIN warning can mean a damaged number or a code that belongs to a different product. Find the cause before editing the field.
| Problem | What to check | Practical correction |
|---|---|---|
| Number is missing | Has this exact item been assigned a GTIN? | Ask the manufacturer or supplier; leave the field blank if none exists |
| Number has an unexpected length | Lost leading zeros, truncation or an internal code | Return to the original label or product record |
| Number contains letters | SKU or MPN entered in the GTIN field | Move the value to the appropriate field |
| Check digit fails | Mistyped, missing or reordered digits | Reconfirm the complete assigned number |
| Checksum passes, but Google rejects the GTIN’s prefix | Google’s restricted ranges (02, 04 or 2) and coupon ranges (05, 98 or 99) | Recheck the original GTIN with the supplier. Do not change its prefix to force acceptance |
| Number passes but describes another item | Wrong model, size, color or packaging level | Replace it only with the confirmed GTIN for this item |
| Same number appears on different variants | A shared parent value was copied to every row | Check the GTIN assigned to each variant |
How the check digit works
The final digit of a GTIN is a check digit. For the preceding digits, work from right to left and multiply by 3, then 1, alternating. Add the results. The check digit is the amount needed to reach the next equal or higher multiple of ten.
Educational example only: start with the 12 digits 123456789012 and work out a GTIN-13 check digit. This exercise does not show that GS1 assigned the code to anyone. The result must not be submitted as a real product identifier.
For this payload, the calculation is:
- Digits weighted by 1:
1 + 3 + 5 + 7 + 9 + 1 = 26. - Digits weighted by 3:
(2 + 4 + 6 + 8 + 0 + 2) × 3 = 66. - Weighted total:
26 + 66 = 92. - Check digit:
100 − 92 = 8.
The educational result is 1234567890128. It passes the checksum. It still provides no evidence of who assigned it or which product it identifies.
Do not fix a real catalog number by changing its last digit to pass this check. Confirm the original number first. A wrong number can still pass the checksum.
Preserve zeros and recognize UPC-E
Store GTINs as text in spreadsheets and databases so leading zeros survive imports and exports. Remove display spaces or hyphens only after confirming that you have captured the complete number. Do not remove digits to make a value fit a preferred length.
An eight-digit UPC-E symbol needs a separate check. It carries a compressed UPC-A number, so it is not automatically a GTIN-8. For Google Merchant Center, expand UPC-E to the full 12-digit UPC value. Simply adding zeros at the start does not do this.
Check the identifier, then use it in a feed or match
Keep a short sign-off with the product row:
Format check
☐ Correct number format and check digit.
Product check
☐ Evidence ties the number to this brand and model.
Variant and packaging check
☐ Variant, pack contents and sale unit agree.
Apply the destination’s feed rules
For an ordinary Google Merchant Center product row, put the verified GTIN for the exact item or variant in the gtin field. Keep your internal row ID, brand and MPN in their own fields. If the product has no assigned GTIN, check the platform’s rules for the other identifiers. Do not invent a number to fill the gap.
For grouped offers, Google distinguishes who assembled the package:
- Manufacturer multipack or bundle: use the GTIN and other identifiers assigned to that pack or bundle.
- Retailer-created multipack: use the individual product’s identifiers and describe the grouping through the
multipackattribute. - Retailer-created bundle with a main product: use the main product’s identifiers and mark the offer with
is_bundleas required.
These rules apply to Google’s feed. Other marketplaces can have different rules. The same single-item GTIN can appear on a multipack assembled by the seller, so a match still needs a check of the quantity and contents.
When reviewing competitor matches in SkuPeek, use available identifiers alongside the product specifications, variant details, and pack contents before approving a match.
If you then collect prices, save the GTIN and details of the sale unit with each price record. The price scraping guide covers that collection workflow.
The useful outcome is a catalog row whose number, product, variant and packaging agree. A well-formed number is the first check, not the final decision.
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