SSCC Check Digit Calculator

How it is calculated

Enter the 17-digit body of the SSCC, that is, everything except the last digit. Spaces and hyphens are removed first, and anything that does not leave exactly 17 digits (including a full 18-digit code) gives no result. Starting at the rightmost digit of the body, the digits are multiplied by 3, 1, 3, 1 and so on, and the products are added into a sum. The check digit is (10 − sum mod 10) mod 10, the amount needed to bring the sum up to the next multiple of 10 (0 if it is already one). The tool shows the check digit, the full 18-digit SSCC and the weighted sum. Its job is to compute the digit; it does not verify that the company prefix is registered.

Common mistakes

• Pasting the full 18-digit SSCC. The tool wants only the 17-digit body and returns nothing for 18 digits; to check an existing code, enter its first 17 digits and compare the result with the last one.
• Dropping a leading zero, for example when copying from a spreadsheet that turns the number into a plain number. The body must still be 17 digits, so a lost zero changes the count and the weighting.
• Applying the weights from the left. The 3 goes on the rightmost digit of the body, not on the first digit, so a left-to-right calculation gives a different digit.
• Including the application identifier (00) or brackets from a barcode text. The two digits of (00) would be counted as part of the body and the digit count would be 19.
• Assuming a correct check digit means the SSCC is valid in the supply chain. It only shows the arithmetic is consistent; the company prefix and serial reference still have to come from your GS1 allocation.