Calculate and validate barcode check digits

When to check a barcode digit

Check digit calculators catch simple typing errors before a barcode is generated or printed. They do not prove ownership of a number, but they do tell you whether the number passes the expected math rule.

Calculate or validate a check digit

1. Enter the barcode number body to calculate a check digit, or the full number to validate it.
2. Use the EAN, UPC, GTIN, or ISBN-specific calculator when you know the exact format.
3. Compare the calculated or validation result with your product, book, or logistics record.
4. Fix any typing or padding mistake before generating barcode artwork.
5. Remember that a valid check digit is not the same as official number assignment.

Where check digits help

• GTIN checks
• EAN checks
• UPC checks

Number checks before artwork

• Check digits catch common typing errors before labels are printed.
• Use GTIN validation for GTIN-8, GTIN-12, GTIN-13, and GTIN-14 values.
• Use ISBN-specific checks for book identifiers because ISBN-10 and ISBN-13 use different rules.

Check digit mistakes to avoid

• Using a valid check digit as proof that a product, book, or carton number is officially assigned.
• Letting spreadsheets remove leading zeros before validation.
• Mixing EAN, UPC, GTIN, and ISBN rules instead of using the format-specific calculator.

Check digit questions