How to use the gtin-14 and sscc check digit builder
- Pick Check or complete to test numbers, or Make a GTIN-14 to wrap an item number in a case code.
- To test, paste 14 or 18 digit numbers, one per line. Lines with 13 or 17 digits get their check digit added.
- To make a GTIN-14, enter a full GTIN-12 or GTIN-13 with its check digit and an indicator digit from 0 to 8.
- Read the result and copy the finished number.
Formula
from the rightmost data digit, multiply by 3, 1, 3, 1 and so on, then add
check digit = (10 - sum mod 10) mod 10
GTIN-14 = indicator digit + first 12 digits of the GTIN-13 + new check digit
The same weighting covers GTIN-8, 12, 13 and 14 and the 18 digit SSCC. A GTIN-14 is made by pad, replace and recalculate: the old check digit is dropped and a new one is worked out.
A case code for 4006381333931
The GTIN-13 4006381333931 has the data digits 400638133393. With the indicator digit 1 in front, the 13 data digits are 1400638133393. Weighting from the right by 3, 1, 3, 1 and so on gives a sum of 92, so the check digit is 8 and the GTIN-14 is 14006381333938.
The page also confirms that 10614141000415 is a valid GTIN-14, that 106141412345678977 is a valid SSCC-18, and that changing the last digit of the first to 6 makes it fail with the expected digit 5.
Indicator digits and packaging levels
The first digit of a GTIN-14 is an indicator chosen by the company that packs the goods. Many companies use 1 for a case of the same item, but the meaning is theirs to define.
The page only does the arithmetic. It cannot tell who owns a company prefix or what a number refers to.
What an SSCC is
An SSCC is an 18 digit serial shipping container code used to identify a pallet or parcel. It is a data string with 17 digits followed by the check digit, and it uses the same 3 and 1 weighting.
For UPC-A, EAN-13 and EAN-8 numbers, use the Check Digit Validator. To print a barcode from the finished number, use the Barcode Generator.
Assumptions and limits
- The tool checks the arithmetic only. It does not know who owns a company prefix.
- Make mode needs a full GTIN-12 or GTIN-13 whose own check digit already works.
- Indicator digits from 0 to 8 are accepted. 9 is reserved for variable measure items and is not offered.
- Nothing you type is stored or sent anywhere.
- Up to 200 lines are read at once.
Frequently asked questions
Why is 9 not allowed as the indicator?
In GS1 numbering, an indicator of 9 marks variable measure trade items, which follow different rules. This page keeps to the fixed packaging levels from 0 to 8.
Do I need to change the number when I add an indicator digit?
Yes. The old check digit is dropped and a new one is worked out for the longer number, because every digit now sits one place further from the right.
Can the same check be used for a GTIN-12?
Yes. GTIN-12, GTIN-13 and GTIN-14 all use the 3 and 1 weights from the right, so the check digit rule is the same. Only the length changes.
Does a valid check digit make a code usable at a store?
No. A retailer or a registry decides whether a code is accepted. The check digit only shows that the code was typed or built correctly.