TXT · Text & Data tools

UPC-A Check Digit Calculator

Batch by newline

Values to check

Result

UPC-Ascheme0values0valid0invalid0unreadable

The 12-digit North American retail barcode number.

Open the full check digit validator with Luhn, IBAN, ISBN, GTIN, VIN, ISIN, Verhoeff, and Damm

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Settings are written to the URL as you change them. Nothing differs from the defaults yet.

The 3-1 weighting

UPC-A is a 12-digit number: an 11-digit body and a check digit. Weights alternate 3 and 1 from the left, the reverse of the EAN-13 pattern, because the payload has an odd length.

Both are the same rule underneath. Weights always alternate 3 and 1 counting leftwards from the check digit, and only the parity of the payload decides which weight lands first.

UPC-E

A UPC-E is a compressed 8-digit form of a UPC-A. Its check digit belongs to the expanded 12-digit number, not the compressed one, so an 8-digit UPC-E will not validate here. Expand it first, then check.

Frequently Asked Questions

How is the UPC-A check digit calculated?

Weight the digits alternately 3 and 1 from the left, sum them, then subtract the total from the next multiple of 10.

Why does my UPC pass as an EAN-13 with a leading zero?

A UPC-A padded to 13 digits with a leading zero is the same number under the GTIN rules, so the check digit does not change.

What input does it accept?

Paste one 12-digit number per line. Spaces and dashes are stripped before the check runs.

Pages locked to one scheme

Full Check Digit Validator tool

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009ISSN Validator

010Luhn Algorithm Calculator

011Verhoeff Algorithm Calculator

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