Barcode & ISBN Checker
Paste the digits printed on a package or a book, and find out which barcode format it is, whether the check digit adds up, and what the number actually says.
Barcode & ISBN Checker
Paste the digits printed on a package or a book, and find out which barcode format it is, whether the check digit adds up, and what the number actually says.
About the barcode & ISBN checker
Why books and products share one tool
An ISBN-13 is an EAN-13 that begins with 978 or 979, and a UPC-A is an EAN-13 with a leading zero. They all use the same mod-10 weighted checksum, so one tool covers the whole family. When you have a string of digits in your hand you often do not know whether it belongs to a book or a product - that is exactly what the tool tells you first.
The prefix is not the country of manufacture
This is the most common misreading of a barcode. The prefix identifies the GS1 member organisation that issued the company its number range - a company registered in one country can have its goods made anywhere. Some prefixes are not countries at all: in-store codes, coupons and GS1 Global Office allocations are labelled as such rather than mapped to a flag.
What is deliberately left out
UPC-E is not supported: an eight-digit UPC-E and an EAN-8 have the same length and can both start with 0 or 1, so there is no reliable way to tell them apart - guessing would produce a confident wrong answer. The tool also does not generate barcode images or check-digit samples, and it does not look up product records; the only external lookup is the public book catalogue, and it only runs for a valid ISBN.
FAQ
Common questions and answers about this topic.
What is the last digit of a barcode for?
It is a check digit, calculated from all the digits before it with alternating weights of 3 and 1. Scanners use it to catch misreads on the spot - if a single digit is read wrong, the arithmetic no longer works out and the scan is rejected instead of silently ringing up the wrong item.
What is the difference between an ISBN and a product barcode?
Structurally, very little. An ISBN-13 is an EAN-13 whose first three digits are 978 or 979, a range GS1 reserved for books. The difference is what the middle digits mean: a product barcode carries a company number and an item number, while an ISBN carries a language or area group and a publisher.
If the check digit is correct, does the product or book really exist?
No. A correct check digit only proves the digits are internally consistent - anyone can make up a number that passes. Proving something exists requires a catalogue, which is why the book lookup is a separate, clearly labelled section rather than part of the verdict.
Why are some barcodes 8 digits and others 13?
EAN-8 exists for packages too small to carry a full EAN-13 - chewing gum, small cosmetics, single-serve items. It is allocated more sparingly because it holds far fewer item numbers. UPC-A's 12 digits are the older North American form, which became an EAN-13 with a leading zero when the two systems merged.
Do the first three digits really tell you where a product was made?
No, and this is probably the most widely repeated barcode myth. The prefix identifies the GS1 member organisation that issued the number range to the company, so it reflects where the brand registered, not where the goods were made. A brand registered in one country routinely manufactures elsewhere, and the barcode does not change. Some prefixes are not countries at all - in-store codes, coupons and GS1 Global Office allocations - and this tool labels those honestly instead of mapping them to a flag.
Why can some valid ISBNs not be found?
The title comes from Open Library, a public catalogue whose coverage is uneven - it is strongest for English-language and widely held titles, and much thinner for small presses, regional publishers and recent releases. A missing record says nothing about the number itself; the check digit result above is calculated from the digits and does not depend on any catalogue.