Validate ISBN-10 and ISBN-13, convert between them, see the barcode and look up title, author, publisher and cover.
The ISBN (International Standard Book Number) is the number that identifies one edition of a book in the publishing trade. This tool puts together what usually takes several sites: it validates ISBN-10 and ISBN-13 by their check digit and shows the calculation step by step, tells you which digit would be right when you mistyped, converts one format into the other, splits the number into prefix, registration group, publisher, title and check digit with hyphens taken from the International ISBN Agency's official ranges, and draws the EAN-13 barcode as SVG or PNG. When you want to know which book a number belongs to, the lookup fetches title, authors, publisher, year, page count and cover from BrasilAPI and Open Library, shows which source each detail came from, and builds an ABNT or APA reference from what it found. There is also a tab for pasting a whole list of ISBNs, validating them at once and exporting the result as CSV.
An ISBN-13 has five parts. The prefix is 978 or 979, the two GS1 prefixes used on books. Next comes the registration group, which corresponds to a country, region or language and is defined by the International ISBN Agency: 0 and 1 are English language, 2 is French language, 3 is German language and, for Brazil, 65 and 85 under the 978 prefix. Then comes the publisher (the registrant), which receives a block of numbers from its national agency, then the publication number, which the publisher itself picks for each title and edition, and finally the check digit.
Each block has a variable length, so you cannot tell where the group ends and the publisher begins just by counting digits. That is why hyphenation depends on a range table published by the International ISBN Agency. This tool uses that table and, when a number falls into a range that is not yet assigned, it prefers to show the blocks without hyphens rather than guess a wrong split.
In ISBN-13, each of the first 12 digits is multiplied by 1 and 3 alternately and the products are added up. The check digit is whatever is needed to reach the next multiple of 10. In 978-0-306-40615-7 the sum of the first 12 is 93, the remainder when divided by 10 is 3, and 10 minus 3 is 7. This method catches any single-digit change and most swaps of two neighboring digits, but it misses swaps of digits that differ by 5.
In ISBN-10, the first 9 digits get weights from 10 down to 2 and the sum is divided by 11. In 0-306-40615-2 the sum is 130, the remainder is 9, and 11 minus 9 is 2. When the result is 10, the digit written is the letter X. This modulus catches every single-digit error and every swap of two neighboring digits. A number with the right check digit is well formed, but that does not prove the book exists: only a catalog lookup answers that.
A book's barcode is the ISBN-13 itself written as an EAN-13: the 13 positions are the same, just drawn as bars. The ISSN, on the other hand, identifies serial publications such as magazines and journals, not a book edition. It has 8 digits (the last can be X) and, in a magazine's barcode, it goes into an EAN-13 that starts with 977 instead of 978 or 979.
Each format of a work gets its own ISBN: the print edition, the EPUB ebook and the PDF, for example, should be identified separately, and a new edition or translation also needs a new number. That is why the same work shows up with several ISBNs, and it is worth trying more than one when a lookup finds nothing.
The Brazilian Book Chamber (Câmara Brasileira do Livro, CBL) is the Brazilian ISBN Agency: the International ISBN Agency appointed it to run the service in the country starting 1 March 2020. CBL assigns the number ranges to the publishers and authors who publish. Brazil's registration groups are 65 and 85, under the 978 prefix.
To find the ISBN on a printed book, look at the copyright page (on the back of the title page, next to the cataloging data) and at the back cover, where the number appears above or beside the barcode. In ebooks it is usually on the file's copyright page and on the store page.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
<iframe
src="https://jkit.tools/embed/en-US/isbn-lookup-br"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="ISBN Lookup Brazil"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
ISBN stands for International Standard Book Number. It is the identifier of a book edition, used by publishers, bookstores, libraries and online stores for cataloging, sales and stock control. Each edition and each format of the same work should have its own.
Open in a new tab. The catalog may not have the book.
Validating, converting, the anatomy view, the barcode and batch processing all happen in your browser. Only the Look up book tab sends the ISBN: to the jkit.tools server, which forwards it to BrasilAPI, and to Open Library. Google Books is only queried if the other two do not find the book.