I did this brief information paper for the staff at work. Thought this would be a good place for it to go for others who may have a passing interest in knowing more about ISBN 13.

As of 1st January 2007, International Standard Book Numbers (ISBNs) will be 13 digits long, extended from the current 10 digits. ISBN’s are unique identifiers, assigned to each edition of a book and book like product. (eg. Hardback, paperback, audio, e-book etc) This information paper will give some brief background on why it is happening and how it may affect library staff.

1. Why is the ISBN changing to 13 digits?
ISBNs came into being in the 1960s, but with the expansion of publishing into digital, amongst other changes, the capacity of the 10 digit system is fast dwindling. The expansion to 13 digits brings the ISBN into line with EAN-UCC International product coding system for barcodes – which is already 13 digits long.

2. What will happen to existing 10 digit ISBNs?
Existing 10 digit ISBNs will be translated into 13 digits, by adding the 978 prefix to the start of number and recalculating the check digit at the end. Therefore, as can be seen on some books already, they will have both a 10 and 13 digit ISBN – one is translatable into the other.

Eg. ISBN10 = 1-55853-234-X corresponding to ISBN13 = 978-1-55853-234-2

3. Adding a fixed 3 digit prefix won’t expand the range of ISBN’s though.
That’s correct, which is why once the 978 prefixes have been exhausted, new ISBN’s will be issued with the 979 prefix, effectively doubling the number of ISBN’s.

4. I want to check for an item by ISBN, but it’s a 10 digit one and it’s after Jan 2007, what can I do?
If there is a publisher’s barcode on the back of the item, just use that as it already represents the new ISBN13. If it doesn’t have a barcode, ISBN 10s can be translated to ISBN 13, just add the 978 prefix and recalculate the check digit. If you can’t find the formula to do that, try searching on the truncated 12 digit number. HOWEVER, it can only work in the reverse if the ISBN13 has a 978 prefix. With the new 979 prefixes that are coming out before the end of the decade, there will be no ISBN10 equivalent.