ISBN Calculator

The ISBN Calculator is a free tool made available by the International ISBN Agency for publishers across the world and we guarantee that our calculator is fully accurate and up to date for all valid ISBN ranges.  It is designed primarily to allow publishers to calculate the valid ISBNs from a prefix that they have been legitimately assigned by their national ISBN agency. It can also be used to convert the old 10-digit ISBNs (which should no longer be quoted) into their correct 13-digit counterparts. If you have only received a single ISBN from your national ISBN Agency you cannot use the Calculator – you must contact your national ISBN agency if you need more ISBNs.

Please note that the ISBN Calculator cannot be used to obtain a new allocation of ISBNs. Publishers should always obtain their ISBNs from their national ISBN agencies. In fact, access to the ISBN calculator is restricted and any publishers wishing to use this facility must contact their national ISBN agency to request access details. Some of our national ISBN agencies will require publishers to provide information about their publications before they provide access.

To gain access to the ISBN calculator, please click here for contact details of your national ISBN agency. If you already have log-on credentials, please log-on to use the calculator.