Work out the last digit of a UPC, EAN, GTIN, SSCC, GLN or ISBN, or check whether a full number is valid. The calculation is shown step by step.
Result
Enter a number to see the result.
How the GS1 check digit works (UPC, EAN, GTIN, SSCC)
Every GS1 number ends in a check digit calculated with the modulo 10 method:
Take all digits except the check digit.
Starting from the right, multiply the digits alternately by 3, 1, 3, 1…
Add up the results.
The check digit is the number you add to reach the next multiple of 10 (0 if the sum already is one).
Worked example: UPC-A 03600029145_
From the right, the digits 5, 4, 1, 9, 2, 0, 0, 0, 6, 3, 0 are multiplied by 3, 1, 3, 1… giving 15 + 4 + 3 + 9 + 6 + 0 + 0 + 0 + 18 + 3 + 0 = 58. The next multiple of 10 is 60, so the check digit is 2 and the full UPC is 036000291452.
ISBN-10 check digit
Multiply the first nine digits by 10, 9, 8 … 2, add them, and find the number that makes the total divisible by 11. A result of 10 is written as X. To convert an ISBN-10 to ISBN-13, put 978 in front of the first nine digits and calculate a new EAN-13 check digit; the calculator does this for you.
Which number do I have?
8 digits: EAN-8, used on small packages.
12 digits: UPC-A, used in the US and Canada.
13 digits: EAN-13 (most of the world), ISBN-13 for books (starts 978/979), or a GLN location number.
14 digits: GTIN-14 for cases and cartons, printed as ITF-14 or GS1-128.
It is the last digit of a barcode number. It is calculated from the other digits, so a scanner can detect most typing and reading mistakes.
How is the UPC/EAN/GTIN check digit calculated?
Starting from the rightmost digit before the check digit, multiply digits alternately by 3 and 1, add the results, and take the amount needed to reach the next multiple of 10. That amount (0–9) is the check digit.
Do UPC, EAN and GTIN use the same check digit?
Yes. GTIN-8 (EAN-8), GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14, GLN and SSCC-18 all use the same GS1 modulo 10 method.
How is the ISBN-10 check digit different?
ISBN-10 uses modulo 11 with weights 10 down to 2. If the result is 10, the check character is X. ISBN-13 uses the same method as EAN-13.
Does a valid check digit mean the barcode is registered?
No. It only proves the number is well-formed. Real product numbers must come from a GS1 member organisation; you cannot create a valid company prefix yourself.
Can I make a barcode from the result?
Yes. Use the buttons under the result to open the UPC, EAN or ISBN barcode generator with the number filled in.