Barcode Check Digit Calculator
Calculate or verify EAN, UPC, and ISBN check digits.
Barcode formats have different character, capacity, and check-digit rules. Generate, scan, and validate formats; conversion is not always lossless.
Check Digit
Calculate or verify EAN, UPC, and ISBN check digits.
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How to calculate a barcode check digit
Check digits catch common typing and scanning errors; they do not encrypt data or prove that an identifier is registered. Choose EAN-13, UPC-A, ISBN-10, or ISBN-13, then enter only the data digits. The completed code and calculated final character are produced locally using the format’s weighting rule.
Nothing you enter or upload is sent to a server, saved, or shared.
Use it in three steps
- Choose the identifier format.
- Enter the required digits without the final check digit.
- Copy the calculated digit or completed number and verify it against the source.
Practical example
Frequently asked questions
What does a check digit prove?
Only that the number passes its arithmetic error-detection rule.
Why can ISBN-10 end in X?
X represents the value ten in the modulus-11 calculation.
Are UPC and EAN rules identical?
They use the same modulus-10 weighting pattern but different data lengths.