ISBN Checker and Converter
Validate ISBN-10 and ISBN-13 check digits, convert between them, add hyphens and see the barcode digits, singly or in bulk.
Hyphens, spaces and an "ISBN" label are ignored.
Enter an ISBN to check it.
About ISBN Checker and Converter
Checks whether an ISBN-10 or ISBN-13 has a correct check digit, converts between the two forms, adds hyphens where the number falls in a known range, and shows the EAN-13 barcode digits that go on the back cover.
Type or paste one ISBN to see the result straight away, or switch to Bulk and paste a list (one per line) to get a table you can download as CSV. If the check digit is wrong, the tool shows the digit it should be.
A wrong check digit most often means a mistyped or swapped digit. Compare the number with the copyright page or the publisher listing before you correct it: the suggested last digit only makes the number mathematically valid, it does not prove the book exists.
- How is the ISBN check digit calculated?
- For an ISBN-13, the first twelve digits are multiplied alternately by 1 and 3, added up, and the check digit is whatever brings the total to a multiple of 10. For an ISBN-10, the first nine digits are multiplied by 10 down to 2, added up, and the check digit makes the total a multiple of 11, with X standing for 10.
- How do I convert an ISBN-10 to an ISBN-13?
- Put 978 in front of the first nine digits of the ISBN-10, drop its old check digit and calculate a new ISBN-13 check digit. The tool does this for you. The reverse works only for numbers that start with 978, because 979 numbers have no ISBN-10.
- What does the tool do when the check digit is wrong?
- It shows the digit the check digit should be, assuming the other digits are right, and shows the converted forms using that digit. It cannot tell which digit you mistyped, so confirm the number against the book or the publisher.
- Why are some ISBNs not hyphenated?
- Where the hyphens go depends on range tables from the International ISBN Agency. The tool includes the English groups and several large groups. For any other group it shows the clean digits and states that hyphenation was not done, instead of guessing.
- Is the barcode the same as the ISBN?
- The barcode on a book is an EAN-13 that encodes the ISBN-13 digits, so the digits under the bars are the 13 digits of the ISBN. The preview in the tool lets you check them. Printers and distributors usually generate the barcode graphic for the cover.
How to use ISBN Checker and Converter
Type or paste an ISBN into the box. The result appears at once: whether the check digit is correct, the ISBN-13 and ISBN-10 forms, the hyphenated form where it is available and the digits of the EAN-13 barcode. For a list, open the Bulk tab, paste one ISBN per line and download the table as CSV.
When to use it
Use it before you enter an ISBN into a publishing dashboard, a metadata sheet or a catalog, when a number from a spreadsheet or a scan looks wrong, or when a system wants the other form (ISBN-10 or ISBN-13). The bulk tab suits a backlist or an import file you want to check in one pass.
When not to use it
Do not use it to find out who owns an ISBN, whether a book exists or whether a number has been assigned. A number with a correct check digit is only well formed. Look the number up with your ISBN agency or a book database for that.
Tips for best results
When the check digit is wrong, the tool suggests the last digit that would make the number valid. Compare it with the copyright page before you use it, because a different digit earlier in the number may be the real mistake. The barcode preview is for checking digits; use the barcode your printer or distributor supplies for the cover file.
Limitations
Hyphenation uses the International ISBN Agency range tables for the English groups (978-0, 978-1, 979-8) and several large groups (French, German, Japanese, Russian, Chinese, Spanish, Italian, 979-10). Other groups are shown without hyphens and the tool says so. Ranges are reassigned over time, so hyphen positions can differ from an older printed book. 979 numbers have no ISBN-10 form.
Privacy
The numbers are checked in your browser tab with simple arithmetic. They are not uploaded or stored, and the CSV is created on your device.
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