Barcode Check Digit Calculator (EAN, UPC, ISBN)
Work out or verify the check digit of an EAN-13, UPC-A, EAN-8, GTIN-14 or SSCC, with the sum shown, and convert ISBN-10 to ISBN-13 and back.
Answer
| Digit | 4 | 0 | 0 | 6 | 3 | 8 | 1 | 3 | 3 | 3 | 9 | 3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| × weight | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 |
| = | 4 | 0 | 0 | 18 | 3 | 24 | 1 | 9 | 3 | 9 | 9 | 9 |
Sum 89; up to the next multiple of 10 is 90, so the check digit is 1.
Number
How is this calculated?
GS1 (EAN, UPC, GTIN-14, SSCC): weights 3, 1, 3, 1 … from the right of the digits before the check; check digit = (10 − sum mod 10) mod 10. ISBN-10: weights 10 down to 2 on the first nine digits; check = (11 − sum mod 11) mod 11, written X for 10. ISBN-13 is 978 + the first nine digits of the ISBN-10, with a GS1 check digit.Runs in your browser — nothing you enter leaves this device.
About this tool
What it does
Barcode Check Digit Calculator works with the last digit of retail and logistics barcodes, which exists only to catch mistakes. Type a complete EAN-13, UPC-A, EAN-8, GTIN-14 or SSCC-18 and it says whether the check digit is right; type the number without its last digit and it works the check digit out. Either way, the sum behind it is shown digit by digit — each digit, its weight of 3 or 1, and the products — so you can follow it or check it by hand. A second mode handles book numbers: type an ISBN-10 or ISBN-13 and it checks it and gives the other form, so a ten-digit ISBN from an old book becomes the thirteen-digit one used on today’s barcodes, and back. It is useful when entering products into a billing or inventory system, checking a supplier’s list, or finding which digit of a mistyped code is wrong.
How to use it
- Choose Barcode or ISBN.
- Type the number; spaces and hyphens are ignored.
- For 12 or 13 digits, say whether the check digit is included or should be added.
- Read the answer and the working underneath.
Limits and your data
- A right check digit means the number is well formed, not that it is registered to a product. Only GS1’s registry says who owns a number.
- The check catches every single wrong digit and most swaps of neighbouring digits, but not every error: two mistakes can cancel out.
- 12 and 13 digits are ambiguous — a complete UPC-A, or an EAN-13 missing its check digit — so the page asks which you mean.
- ISBNs starting 979 were never issued as ten-digit numbers, so they have no ISBN-10.
- Hyphenation of ISBNs depends on registration-group tables that change over time, so the ISBN-13 is grouped only after its 978 or 979 prefix.
- Everything is worked out in your browser; nothing you type is sent.
Questions
How is the EAN-13 check digit calculated?
Multiply the first twelve digits alternately by 1 and 3, starting from the left with 1, add the results, and take the amount needed to reach the next multiple of 10. For 400638133393 the sum is 89, so the check digit is 1.
How do I convert ISBN-10 to ISBN-13?
Put 978 in front of the first nine digits and work out a new check digit with the GS1 method. 0-306-40615-2 becomes 978-0306406157. The page does it for you in ISBN mode.
Why is there an X in some ISBNs?
The ISBN-10 check is calculated modulo 11, so it can come to 10, which is written as X to keep the number ten characters long.
Is a UPC-A the same as an EAN-13?
A UPC-A is an EAN-13 starting with 0, with the 0 left off. The check digit is the same either way.