UPC check digit calculator

UPC-A barcodes

The Universal Product Code was the first barcode scanned at a supermarket checkout, in 1974. UPC-A, its standard form, has 12 digits: a number-system digit, a manufacturer number, a product number and a check digit. It is still the barcode on most products in the United States and Canada; GS1 calls the number a GTIN-12.

How it is calculated

Add the digits in the odd positions (1st, 3rd, 5th… of the first 11) and multiply by 3. Add the digits in the even positions. The check digit is what brings the total to the next multiple of 10.

Worked example

03600029145: odd positions 0 + 6 + 0 + 2 + 1 + 5 = 14, × 3 = 42; even positions 3 + 0 + 0 + 9 + 4 = 16; total 58. The next multiple of 10 is 60, so the check digit is 2: 036000291452.

Put a 0 in front of a UPC-A and you have the EAN-13 for the same product, with the same check digit.

The page removes spaces and hyphens. With 11 digits it computes the check digit with the GS1 mod-10 algorithm, weighting digits 3 and 1 alternately from the right of the payload; with 12 digits it recomputes the check digit from the first 11 and compares. The algorithm is identical to EAN-13's, so UPC and EAN check digits always agree for the same product. Everything runs in your browser.