Check digit calculator and GTIN checker for UPC, EAN and SSCC.
Calculate the check digit for any GS1 number, or paste a whole column of EAN, UPC and ISBN barcodes. Each number is checked for length and check digit, matched to the GS1 office that issued its prefix, and flagged if it is the kind of number Google and marketplaces reject.
FreeNo accountRuns in your browser
Check digit calculator
Enter a number without its last digit to get the check digit and the full GTIN, UPC, EAN or SSCC. One per line for a whole column.
Check barcode numbers in bulk
Paste up to 5,000 complete numbers: each one is checked for length, check digit, issuer and whether Google accepts it.
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How the check digit is calculated
One rule for UPC, EAN, GTIN-14 and SSCC
Every GS1 number ends in a check digit worked out from the digits before it, so the calculator above and GS1’s own check digit calculator always agree. Here is the EAN-13 4006381333931, worked by hand.
Step 1
Weight the digits
Take the 12 digits before the check digit, 400638133393. Starting from the right, multiply them by 3, 1, 3, 1 and so on.
Step 2
Add them up
3×3 + 9×1 + 3×3 + 3×1 + 3×3 + 1×1 + 8×3 + 3×1 + 6×3 + 0×1 + 0×3 + 4×1 gives 89.
Step 3
Round up to ten
The next multiple of ten is 90, so the check digit is 90 minus 89: 1. The full number is 4006381333931.
Every length
Same steps
A UPC-A uses 11 digits, an EAN-8 uses 7, a GTIN-14 uses 13 and an 18-digit SSCC uses 17. The weights always start at 3 on the right.
What the bulk check tells you
Whether a number is real enough to list
Google Merchant Center, Amazon and most marketplaces reject an invalid GTIN, and an invalid one is worse than none. Each number gets four answers.
1. Shape
Length and type
8, 12, 13 or 14 digits (EAN-8, UPC-A, EAN-13, ITF-14), or a 10-digit ISBN converted to its 13-digit GTIN.
2. Check digit
Typos caught
The last digit is calculated from the rest. A wrong one almost always means a mistyped or made-up number, and the tool shows what it should be.
3. Prefix
Who issued it
The GS1 member organisation behind the company prefix, from GS1’s own list, and whether the range is for books, coupons or in-store use only.
4. The 14-digit form
One format for every feed
Every valid number padded to 14 digits, the form Google and GS1 accept everywhere, ready to download as a CSV.
Barcodes are fine but the product page still is not showing in Google Shopping? Check its markup with the free schema checker, then check the whole feed with the Product Feed Checker.
Questions
About the GTIN Checker
What is a GTIN?
A GTIN (Global Trade Item Number) is the number under a product barcode. It comes in four lengths: 8 digits (EAN-8), 12 (UPC-A, common in North America), 13 (EAN-13, used in most other countries) and 14 (ITF-14, for cases and packs). ISBNs on books are GTINs too.
How do I check an EAN barcode?
Type or paste the digits printed under the barcode, all 13 of them for an EAN-13, into the box above. The checker confirms the length and the check digit, shows the GS1 office that issued the prefix, and flags numbers Google will not accept. Paste a whole column from a spreadsheet to check every product at once.
Where do I find a product’s GTIN number?
On the packaging, it is the number printed under the barcode. On Shopify it is the Barcode field on each variant, and on WooCommerce it is the GTIN, UPC, EAN or ISBN field in the product’s Inventory tab. Your supplier or the brand can give you the number if neither is filled in.
How does the check digit work?
The last digit of every GTIN is calculated from the others: counting from the right, digits are multiplied by 3 and 1 in turn, added up, and the check digit is whatever brings the total to the next multiple of ten. A single mistyped digit almost always breaks it, which is how this checker catches typos.
How do I use the check digit calculator?
Type the digits without the last one into the check digit calculator: 7 digits for an EAN-8, 11 for a UPC-A, 12 for an EAN-13, 13 for a GTIN-14 or 17 for an SSCC. The check digit and the full number appear as you type. Paste a column, one number per line, to complete thousands at once and download them as a CSV.
Does it work as a UPC and GS1 check digit calculator?
Yes. UPC, EAN, GTIN-14, SSCC and GLN numbers all use the same GS1 rule, so this works as a UPC check digit calculator, an EAN check digit calculator and a GS1 check digit calculator in one, and its answers match the calculator on the GS1 website.
How many numbers can I check at once?
Up to 5,000 in one paste, in the bulk checker and in the calculator alike. Everything runs in your browser, so a full column from a spreadsheet takes a moment and nothing is uploaded.
Can I make my own barcode numbers with the calculator?
No. The calculator completes a number you already have. A GTIN or UPC that will be accepted by Google and marketplaces has to come from a company prefix licensed from GS1, or from the brand that owns the product. A number built from made-up digits will pass a check digit test and still be rejected as someone else’s or as unlicensed.
Does a valid check digit prove the number belongs to my product?
No. It proves the number is well formed. Only the brand that licensed the number from GS1 can assign it to a product. GS1 runs a free lookup, Verified by GS1, that shows which company a number is registered to.
Does the prefix tell me where a product was made?
No. The first digits show which GS1 member organisation issued the company prefix, for example GS1 UK or GS1 Germany. A brand can license numbers in one country and manufacture anywhere.
Why does it reject numbers starting with 2?
Prefixes 020 to 029, 040 to 049 and 200 to 299 are restricted circulation numbers: shops use them for items weighed or priced in store, and they mean nothing outside that store. Google Merchant Center and marketplaces reject them as product identifiers.
What if my product has no barcode?
In a Google Merchant Center feed, give the brand and the manufacturer part number (mpn) instead, or set identifier_exists to no for products such as handmade items that never had one. Never invent a GTIN: an invalid or borrowed number is worse than none.
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