Barcode Number Checker

Check the length and check-digit mathematics of a UPC, EAN, GTIN, ITF-14, UPC-E, ISBN-10, or ISBN-13 number. Use automatic detection or require one exact number type.

Spaces and hyphens are ignored. ISBN-10 may end in X. Leading zeroes are preserved.

Use automatic detection or require one exact format.

Try a verified sample

Ready to check a number

Enter a supported number or load one of the verified samples above.

Validation runs in browser-side code. The entered number is not placed in the page URL or sent to a product database.

Supported number types

The checker uses the shared validation module to validate GTIN, EAN, UPC, and ISBN numbers in the configured formats below. Some values can match more than one naming convention, so automatic detection may report several compatible candidates.

  • GTIN-8
  • EAN-8
  • GTIN-12
  • UPC-A
  • UPC-E
  • GTIN-13
  • EAN-13
  • ISBN-13
  • GTIN-14
  • ITF-14
  • ISBN-10

GTIN, UPC, and EAN

GTIN-8, GTIN-12, GTIN-13, GTIN-14, UPC-A, EAN-8, and EAN-13 use GS1 Mod 10 check-digit mathematics. UPC-E is expanded to its equivalent UPC-A structure before its check digit is evaluated.

ISBN-10 and ISBN-13

ISBN-10 uses a Mod 11 calculation and may end in X. ISBN-13 uses the same Mod 10 pattern as EAN-13 and must begin with a 978 or 979 book prefix.

How the check-digit validator works

Four steps take the checker from a raw entry to a check-digit result for each applicable number type.

  1. Normalize the entry

    Spaces and common hyphen characters are removed while leading zeroes and an ISBN-10 X are preserved.

  2. Check the structure

    The selected type or detected length determines which number structures can be evaluated.

  3. Calculate the digit

    The checker applies GS1 Mod 10 or ISBN-10 Mod 11 to the payload before the final check character.

  4. Compare the result

    The calculated check digit is compared with the supplied digit and reported for each applicable candidate.

Automatic detection or an exact type

Automatic detection is useful when you only have the number. It uses the normalized length and known prefixes to show possible number types and candidate results — handy when you scan a barcode number off a label and are not sure which symbology produced it.

Select an exact type when the label, document, or source system already identifies the format. Exact validation also catches a correct check digit attached to the wrong expected length or prefix.

What a valid result does not prove

A check digit is an error-detection mechanism. It can confirm that the supplied characters fit the expected mathematical rule, but it cannot confirm that a number was officially assigned.

Validation does not prove product existence, registration, ownership, authenticity, country of manufacture, current price, or safety. Those questions require an appropriate trusted registry or product database. To learn the math itself, read how barcode check digits work.

Barcode number checker questions

Is this an online barcode checker I can use for a scanned number?

Yes. Paste or type a barcode scan number — UPC, EAN, GTIN, ITF-14, UPC-E, or ISBN — and the online barcode checker validates its length and check digit locally in your browser.

Why can one number have several possible types?

Some naming systems share the same length and check-digit formula. For example, a 13-digit retail number can be described as GTIN-13 or EAN-13, while a 978 or 979 value may also be ISBN-13.

Why is UPC-E expanded to UPC-A?

UPC-E compresses zeroes from a UPC-A number. The checker reconstructs the equivalent UPC-A payload and uses that structure to verify the UPC-E check digit.

Why does an ISBN-10 sometimes end in X?

ISBN-10 uses Mod 11. When the calculated check value is ten, the single character X represents that value.

Does the checker search for a product or book?

No. It validates number structure locally. It does not query a product, ISBN, publisher, ownership, or GS1 registration database.

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