ISBN validate & convert

Client

Check ISBN-10 (including X check) and ISBN-13 / EAN bookland codes, then copy the alternate form when the prefix is 978. Hyphens and spaces are ignored; nothing leaves your tab.

What this covers

Publishers assign ISBNs; this page only verifies the check characters and converts between the ten-digit legacy form and the thirteen-digit GTIN-style code when the math allows. It does not replace Bowker, national ISBN agencies, or retailer APIs.

How to use

Paste one identifier per box (with or without separators). Use Load example for a known-good ISBN-13, or prefill via ?q= / ?qb= (Base64) for automation. For payment-style digit strings, see Luhn check; for IBANs, see IBAN validate.

Privacy: checks run only in your browser. This tool does not look up titles, publishers, or prices—only checksums and 978↔ ISBN-10 math. Avoid pasting proprietary catalogs on shared screens.
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Hyphens and spaces are ignored. ISBN-10 ends with 0–9 or X (for 10). ISBN-13 is thirteen digits (often starting with 978 or 979). A valid 978 bookland code can be converted to the legacy ISBN-10; 979 codes stay ISBN-13-only.

Result

Valid ISBN-13 9780306406157

ISBN-10 (978 prefix): 0306406152

Common use cases

  • Verify a printed ISBN before importing rows into a catalog or ONIX workflow.
  • Confirm whether a hyphenated ISBN-13 from a pub site survives normalization and still passes the EAN check digit.
  • Derive the legacy ISBN-10 from a 978 bookland ISBN-13 when an older API or template still expects ten characters.
  • Pair with barcode encoding when the payload is the ISBN-13 digit string for an EAN-13 symbol.

Common mistakes to avoid

  • Assuming a passing checksum proves publisher data

    Checksums catch typos in the identifier itself—not whether the assignment is current or the title metadata matches.

  • Expecting an ISBN-10 for every ISBN-13

    979-prefix codes are valid ISBN-13 but do not have a legacy ten-character twin; the tool states that explicitly.

  • Mixing up ISBN check rules with card Luhn

    ISBN-10 uses modulo 11 (hence X). ISBN-13 uses EAN weights. Payment cards use Luhn mod 10—a different tool on Toolcore.

FAQ

Does this confirm a real book exists?

No. Only the mathematical checksums are checked. Publisher assignment and metadata live in external registries.

Why will some ISBN-13 codes not show an ISBN-10?

979-prefix ISBN-13 identifiers are not given a matching legacy ISBN-10. The tool explains that case when it applies.

Is input uploaded?

No. Parsing and checksum math run entirely in your browser tab, like other client-side validators on Toolcore.

How is ISBN-10 validated?

Weights 10…1: the weighted sum must be divisible by 11. A check value of 10 is written as X.

How is ISBN-13 validated?

The same EAN-13 rule applies: alternating weights 1 and 3 over the first twelve digits determine the thirteenth check digit.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • isbn 10 13 validator online
  • convert isbn 13 to isbn 10 978
  • check isbn checksum in browser
  • ean isbn book identifier validate

More tools

Related utilities you can open in another tab—mostly client-side.