What I Already Own

Find a record or book by its barcode or ISBN

Type the barcode or ISBN printed on a record or a book, and What I Already Own finds the exact edition in its catalogue: title, artist or author, year, country, label or publisher, and catalogue number. Vinyl, CDs, cassettes and books, from open databases such as MusicBrainz, Discogs and Open Library. Free, without an account.

Where to find the barcode or ISBN

  • On a bookOn the back cover, usually at the bottom, with the ISBN printed above the bars. It's also on the copyright page, at the front of the book. Books from before 1970 rarely have one.
  • On a record or CDOn the back of the sleeve or case, sometimes on a sticker on the shrink-wrap or on the spine. Fewer than one vinyl record in a hundred pressed before 1985 has a barcode: the catalogue number on the label and spine identifies it instead.
  • On a Japanese bookTwo barcodes are stacked. The upper one, starting with 978, is the ISBN; the lower one, starting with 192, is a price and classification code. Type the upper one.

EAN-13, UPC, ISBN-10 and ISBN-13

Four names for one family of codes. The lookup accepts all of them and converts them to 13 digits before searching.

EAN-13
13 digits: the barcode used outside North America, on records, CDs and books alike.
UPC-A and UPC-E
12 digits, or 8 in the compact UPC-E form: the North American barcode. A leading zero turns a UPC-A into an EAN-13.
ISBN-13
The book number since 2007: 13 digits starting with 978 or 979. It's also the book's EAN-13 barcode.
ISBN-10
The book number before 2007: 10 characters, the last of which can be an X. Every ISBN-10 has an ISBN-13 twin, which the lookup works out for you.

What a barcode tells you

A barcode doesn't identify a work but a product: one edition, one pressing. That makes it the most precise way to know which copy you're holding.

  • The exact edition, not just the title: which printing or reissue of the book or album.
  • For a record, the format and pressing: vinyl, CD or cassette, with the catalogue number that tells reissues apart.
  • The country of release, which often explains a different sleeve, track list or translation.
  • The label that released the record, or the publisher of the book.
  • The year of that edition, sometimes decades after the original release.

What the lookup doesn't do

  • It can't always pick one pressing: when several editions share a barcode, it lists them and you compare.
  • It can't find an item without a barcode. In the app, those are found by title, catalogue number or matrix.
  • It gives no price or value.
  • It doesn't know whether you already own the item: that takes your collection, in the app.

Frequently asked questions

Is the barcode and ISBN lookup free?
Yes. The lookup is free and needs no account. Only keeping a collection in the app requires a subscription, after a 7-day trial.
Where does the data come from?
From open databases that allow commercial reuse: MusicBrainz, the monthly Discogs data dumps (never the Discogs API), Open Library, national libraries and Wikidata. The catalogue is rebuilt every month.
Why isn't my barcode found?
Either a digit was mistyped (the page then says the code doesn't add up), or none of our sources lists that edition yet: often the case for self-published books, very recent releases and small labels. Scanned in the app, an unknown ISBN is looked up in library catalogues the following night.
Can I scan the barcode with my phone instead of typing it?
Yes, in the app: point the camera at the barcode and the edition appears, along with whether it's already in your collection. The app installs from the browser, without the App Store or Google Play.
Is the code I type saved?
It isn't added to any account or list. Our audience measurement records only the outcome of a lookup (found, several editions, not found, invalid), never the code itself.