Check Digit Calculator
Pick the type of code, then type its digits. With one digit fewer than the full length the calculator finds the check digit and gives the complete code. With the full length it checks whether the last digit is correct. It handles EAN-13, UPC-A, EAN-8, GTIN-14, SSCC-18, ISBN-13 and ISBN-10, and converts an ISBN-10 to an ISBN-13 (and back) or a UPC-A to an EAN-13. Spaces and hyphens are ignored. Everything runs in your browser.
The GS1 check digit (EAN-13, UPC-A, EAN-8, GTIN-14 and SSCC-18) is found by multiplying the data digits by 3 and 1 in turn, starting with the digit next to the check digit, adding them up, and taking whatever brings the total to a multiple of 10. An ISBN-10 weights its nine digits from 10 down to 2 and chooses the digit, or X for 10, that makes the sum a multiple of 11. The check digit catches every single-digit mistake, but it does not prove that the code was issued to a product or a book. Everything runs in your browser.
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Developer & WebAbout the Check Digit Calculator
The check digit is the last digit of a barcode or book number, chosen so that a typing mistake is detected. The GS1 rule used by EAN-13, UPC-A, EAN-8, GTIN-14 and SSCC-18 multiplies the data digits by 3 and 1 in turn, starting with the digit next to the check digit, adds them up and takes whatever brings the total to a multiple of 10. For 400638133393 the sum is 89, so the check digit is 1 and the full EAN-13 is 4006381333931. The UPC-A 03600029145 gets the check digit 2, and the EAN-8 9638507 gets 4. An ISBN-13 uses the same rule on a number that starts with 978 or 979. An ISBN-10 multiplies its nine digits by 10 down to 2 and picks the digit that makes the total a multiple of 11, using X when that digit is 10, so 030640615 gets 2 and 097522980 gets X. The ISBN-10 0306406152 becomes the ISBN-13 9780306406157. The check digit catches every single-digit error, but it cannot show that a code was actually issued to a product or a book.
How is the EAN-13 check digit calculated?▾
Multiply the 12 data digits by 3 and 1 in turn, starting with 3 for the digit next to the check digit, add them up, and the check digit is the amount needed to reach the next multiple of 10.
Is a UPC-A the same as an EAN-13?▾
A UPC-A is an EAN-13 with a leading 0. They share the same check digit, so adding a 0 in front of a UPC-A gives a valid EAN-13.
Why does an ISBN-10 sometimes end in X?▾
The check value can be 10, which does not fit in one digit, so it is written as X, the Roman numeral for 10.
How do I convert an ISBN-10 to an ISBN-13?▾
Put 978 in front of the first nine digits and calculate a new check digit with the GS1 rule. The ISBN-10 0306406152 becomes 9780306406157.
Is my data uploaded?▾
No. The calculation runs in your browser and nothing you enter is sent anywhere.