EAN and UPC check digit
Check the check digit of your barcodes
Type an EAN-8, UPC-A or EAN-13 code and see right away whether it is valid, or work out the digit it is missing. It all runs in your browser: nothing is sent.
With 7, 11 or 12 digits it works out the missing one; with 8, 12 or 13 it checks whether the code is valid. Spaces and dashes are ignored.
Type or paste a code with 7, 8, 11, 12 or 13 digits.
How it is worked out
An example with the first 7 digits of an EAN-8. The same rule works for UPC-A and EAN-13.
| Digit | 9 | 6 | 3 | 8 | 5 | 0 | 7 |
|---|---|---|---|---|---|---|---|
| Times | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 |
| Result | 27 | 6 | 9 | 8 | 15 | 0 | 21 |
- From right to left, multiply the digits by 3, 1, 3, 1… The rightmost one is always multiplied by 3.
- Add up the results: 86.
- What 86 is short of 90 is 4, and that is the check digit. If the sum already ends in 0, the digit is 0.
- Put it at the end: 96385074.
Why one wrong digit won't scan
The check digit is a test the scanner runs on every read.
The scanner checks it on every read
When it reads an EAN or UPC, the scanner works the digit out again from the others. If it doesn't match, the read is thrown away, so there is no beep and nothing gets typed.
It catches typos
One mistyped digit always changes the result, and so do almost all swaps of two neighbouring digits. It pays to check a code before you print hundreds of labels.
Atiéndalo adds it for you
When a product has no code, Atiéndalo generates an EAN-8 that is unique in your shop, with the right digit. When you type a manufacturer's code, it checks the digit before saving.
The test label
12345670 is a valid EAN-8. It is the code on Atiéndalo's test label, the one you print to check that your printer prints to scale.
Your code is valid and the label still won't scan? The bar size and the print scale matter too. How Atiéndalo prints its labels
Frequently asked questions
What is a check digit?
It is the last digit of an EAN or UPC code. It is worked out from the other digits, so the scanner can tell when a code was printed or read wrong.
Why won't my label scan?
If the check digit doesn't match, the scanner throws the read away. If the code is valid, check the label size, the print scale and the scanner's settings; the scanner guide covers the usual failures.
Why do 12 digits give me two answers?
Because a full UPC-A has 12 digits, and so does an EAN-13 without its check digit. The tool checks the first and works out the second, and you pick the one that is yours.
Does Atiéndalo check the digit?
Yes. When you save a product with an EAN-8, EAN-13 or UPC-A code, Atiéndalo checks the digit and refuses one that doesn't match. The EAN-8 codes Atiéndalo generates already carry the right digit.
Can I make up an EAN-13 for my products?
The EAN codes used across other shops are assigned to each company by GS1. You don't need one to sell in your own shop, because Atiéndalo gives every product its own EAN-8, unique in your account.
Is the code I type stored?
No. The arithmetic runs in your browser and the code is not sent anywhere.
Another question? The help center has the long answer.
Keep reading
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