UPC Validator and
Check Digit Calculator
A free UPC validator and UPC check digit calculator: check any 12-digit UPC, or find the check digit for 11 digits. Paste one number or a whole list. Nothing is uploaded.
Paste one number or a whole column, one per line. Spaces and dashes are ignored.
Results appear here as you type
Enter 12 digits to check a UPC-A, or 11 digits to find its check digit.
A correct check digit only means the number is well-formed. It doesn’t mean the number is registered, assigned to a product, or yours to use. Check ownership with Verified by GS1.
UPC check digit calculator: how the digit is worked out
The check digit is the 12th digit of a UPC-A. It is worked out from the first 11 so that a scanner, or this page, can catch typos: weight the digits 3, 1, 3, 1… and pick the digit that brings the total to a multiple of 10. For 03600029145 the check digit is 2, so the full UPC is 036000291452.
- Add the digits in the odd positions (1st, 3rd, 5th, 7th, 9th and 11th): 0 + 6 + 0 + 2 + 1 + 5 = 14.
- Multiply that by 3: 14 × 3 = 42.
- Add the digits in the even positions (2nd to 10th): 3 + 0 + 0 + 9 + 4 = 16.
- Add both results: 42 + 16 = 58.
- The check digit takes the total up to the next multiple of 10: 60 − 58 = 2. If the total already ends in 0, the check digit is 0.
Worked example: 036000291452
Each digit times its weight (UPC-A). Weights alternate 3 and 1, starting with 3 at the digit just left of the check digit.
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Digit | 0 | 3 | 6 | 0 | 0 | 0 | 2 | 9 | 1 | 4 | 5 | 2 |
| × weight | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | |
| = product | 0 | 3 | 18 | 0 | 0 | 0 | 6 | 9 | 3 | 4 | 15 | 2 |
- Add the digits in positions 1, 3, 5, 7, 9 and 11: 0 + 6 + 0 + 2 + 1 + 5 = 14. Multiply by 3: 42.
- Add the digits in positions 2, 4, 6, 8 and 10: 3 + 0 + 0 + 9 + 4 = 16.
- Add the two results: 42 + 16 = 58.
- The next multiple of 10 is 60. 60 − 58 = 2, the check digit.
Complete number: 036000291452
The same rule works for every GS1 number (GTIN-8, GTIN-13, GTIN-14): start with weight 3 on the digit just left of the check digit and alternate from right to left. That is why the calculator above also works as a GS1 check digit calculator for GTIN-8, GTIN-13 and GTIN-14. The method is defined in the GS1 General Specifications, section 7.9.
What a UPC’s 12 digits mean
- GS1 Company Prefix (the first digits): identifies the company that licensed the numbers from GS1. Its length varies: companies that need more product numbers get a shorter prefix.
- Item reference (the digits after the prefix, up to the 11th): the brand owner assigns one to each product, size and variant.
- Check digit (the 12th): calculated from the other 11, as above.
The first digit is not a country code. Some first digits do have special uses, and the validator warns about them: 2 for in-store items such as weighed goods, 3 for medicines (the US National Drug Code) and 4 for a company’s internal use. Numbers starting with 5 are reserved by GS1 (they were once used for coupons), so GS1 doesn’t issue them for products.
What this validator can’t tell you
It checks the format and the maths only. It can’t tell you who owns a number, what product it belongs to, or whether you are allowed to use it.
- Who owns it: search the number in Verified by GS1, GS1’s lookup, which shows the company the number was licensed to. It replaced the older GEPIR lookup at the end of 2023 (GS1 support, checked November 2026).
- What product it is: a product lookup service or the retailer’s own catalogue.
- Whether it is yours: only numbers licensed to your company, or bought from GS1 as single GTINs, are safe to use on products you sell. See how to get a UPC from GS1.
We don’t issue, sell or register UPC numbers, and we are not affiliated with GS1. A number that passes here can still be rejected by a retailer or Amazon if it isn’t registered to your brand.
Check digits in Excel
To calculate the check digit for a column of 11-digit numbers in column A (starting in A2), put this in B2 and fill down:
=MOD(10-MOD(3*SUMPRODUCT(--MID(TEXT(A2,"00000000000"),{1,3,5,7,9,11},1))+SUMPRODUCT(--MID(TEXT(A2,"00000000000"),{2,4,6,8,10},1)),10),10)
TEXT(A2,"00000000000") puts back any leading zeros Excel dropped. Join the number and its check digit with
=TEXT(A2,"00000000000")&B2. The same formula works in Google Sheets. Format the result column as Text so Excel doesn’t turn
12-digit numbers into 3.6E+11.
If you are going to print labels anyway, you can skip the formula: the bulk generator checks every row automatically, and the Excel guide covers numbers Excel has already broken.
UPC validator FAQ
How do I calculate a UPC check digit?
Take the first 11 digits. Add the digits in the odd positions (1st, 3rd … 11th) and multiply by 3. Add the digits in the even positions. Add the two results, and the check digit is whatever takes that total up to the next multiple of 10. For 03600029145: (0 + 6 + 0 + 2 + 1 + 5) × 3 = 42, plus 3 + 0 + 0 + 9 + 4 = 16, total 58, so the check digit is 2 and the full UPC is 036000291452.
How can I verify a UPC code?
There are three different checks. This page checks the format: 12 digits with a correct check digit. Verified by GS1 checks ownership: which company the number was licensed to. And a phone barcode app checks the printed barcode: scan your first label before you print the rest.
Is a UPC always 12 digits?
A UPC-A is always 12 digits, leading zeros included. You may also see it as 13 digits with an extra 0 in front (the EAN-13 form of the same number) or 14 digits (GTIN-14). UPC-E barcodes print 8 digits but stand for a 12-digit number. A spreadsheet that drops the leading zero shows 11 digits: the validator spots that and offers the full number for you to confirm.
Why is my UPC check digit wrong?
Usually a typo, two digits swapped, a leading zero lost in a spreadsheet, or a number that was never a real UPC. Go back to the number GS1 or your supplier gave you. Don’t just change the last digit to make it pass: if the mistake is elsewhere, the “fixed” number belongs to a different product.
Does a valid check digit mean the UPC is registered?
No. “Number format looks valid” only means the digits add up. It says nothing about who owns the number or whether it was ever assigned to a product. Registration and ownership come from GS1; check them with Verified by GS1 and read how to get a registered UPC from GS1.
Can I check many UPCs at once?
Yes. Paste up to 1,000 numbers above, one per line, then copy the results or download them as a CSV. To print labels from a list, use the bulk barcode generator: it checks every row and lists problems by spreadsheet row, and makes free PDFs of up to 250 labels.
Number checks out?
Turn it into a print-ready label: pick your label sheet or thermal roll and download the PDF. Free, and no sign-up.
Make a UPC label