GS1 check digit calculator

Got a pallet flagged for an "invalid SSCC" or a label chargeback? Paste the number from your label below. You'll see in a second whether its check digit is right, and what it should be if it isn't.

Works for GTIN-14 case codes, UPC-A, EAN-13, GTIN-8 and SSCC-18 pallet codes. Free, no signup. Nothing you type leaves your browser.

What is a check digit?

The last digit of every GS1 barcode number (GTIN, UPC or SSCC) is a check digit. It's calculated from all the other digits, so a scanner can tell instantly if a number was mistyped or printed wrong. If the last digit doesn't match the math, the scan fails, and the receiving dock treats the label as bad.

How it's calculated

1. Starting from the digit just left of the check digit and moving left, multiply the digits by 3, 1, 3, 1, and so on.
2. Add up the results.
3. The check digit is whatever you add to reach the next multiple of 10. If the sum already ends in 0, the check digit is 0.

Example: for the GTIN-14 1001234567890?, the weighted sum is 88. The next multiple of 10 is 90, so the check digit is 2 and the full GTIN is 10012345678902. Open "Show the math" under any result to see this for your own number.

Why labels end up with a wrong check digit

• Typing it by hand into a label template or spreadsheet, and getting one digit wrong.
• Making up the last digit when building SSCC serial numbers, instead of calculating it.
• Spreadsheets dropping leading zeros, which shifts every digit and breaks the math.
• Copying an old label and changing the serial number without recalculating the check digit.

Other reasons a pallet label gets rejected

A correct check digit is necessary but not enough. Distribution centers also reject labels for a duplicate SSCC (the same number used on two pallets), a barcode that's faded or too small to scan, missing fields such as the PO number, or a label in the wrong spot on the pallet. Each retailer publishes its own requirements on top of the GS1 standard.