ISBN Database Software
Catalog your books by ISBN
Automatically download book details by ISBNLike author, title, publisher, genres, subjects & cover art.
Just search our huge online ISBN database ... ... by ISBN or by author & title.
Over 40 million ISBNs recognizedGuaranteed 97% success rate on your ISBN searches!
CLZ Books
Mobile
Mobile app for your phone or tablet
iOS & Android
iOS & Android
USD $19.95
per year
More about the mobile app
CLZ Books
Web
Web-based software for your computer
Windows & macOS
Windows & macOS
USD $39.95
per year
More about the web app
CLZ Books
Mobile + Web
CLZ Books Mobile
1 year
CLZ Books Web
1 year
USD $0.00
USD $0.00
save USD $0.00
Or... use them both,
as perfect companions!
Both CLZ Books Mobile and CLZ Books Web can be used on their own, as a stand-alone solution. But these tools really come to life when used together, as they are great companions. While away from your computer use CLZ Books Mobile on your phone, then use CLZ Books Web at home, to work on your database on a big screen, with a real keyboard. Of course, you can sync your database between them through our CLZ Cloud solution.
Latest software updates
Sep 1, 2025
My book catalog story
I love my CLZ book catalog. I had always wanted to catalog my books and back in the days of card catalogs when I was young, I made an index card file (which I still have). I had far fewer books then. Now I have about 3,000, with book cases in almost every room of our house, and it is hard to keep track of them all in my head. So, one of the practical reasons for having a catalog is to record the location of each book by room and bookcase and in some cases even by shelf. I just have to remember, if I move a book, to change the location in the location field of my catalog. I have been able to locate books with my catalog instead of wasting time searching from room to room.
I have the mobile version as well, for several reasons. Sometimes when I’m in a bookstore, I am not sure whether I already bought a certain book or not; I can tell it is a title I would have liked to own, but I can’t remember if I actually bought it. At least twice I bought a book I already had. Now I can check my mobile catalog. When I finish reading a book, it is quicker to enter that on the “read” field on my phone than to remember to record it next time I am on my catalog on the computer. I can also stand in front of a bookcase with my phone and check whether all the books are cataloged and whether the location is correct.
Beyond practical reasons, I just love having my books organized and cataloged for mental clarity and the pleasure of looking at the titles and covers on the screen. I had once thought of making my own database of my book collection, but it wouldn’t have been nearly as sophisticated as the CLZ one and wouldn’t have included photos of the book covers. Some of my large categories, such as art books, children's books, and Christmas books, have beautiful colorful covers which are a pleasure to look through on the CLZ catalog. I used the genre field to make up my own categories, many of which are not actually genres but the subjects that are important to me. I love that the CLZ software keeps track of the numbers in each category, so for example I know that at the moment I have 184 art and design books, 248 architecture and interiors, 169 autobiography/memoirs, 102 tea books, 213 on England, 206 on New England, 235 children’s books, and 175 Christmas. It’s just interesting to me to know this. It’s a picture of my interests.
So far I have cataloged 2300 of my books. I really enjoy working on the catalog, but it takes time and not all of my books are easily accessible. My method is to scan my new books right away with the app on my phone that CLZ provides, then add them into the collection when I have time to sit at the computer. Then I go to the backlog of older books as I have time and add them in. Some of the oldest ones pre-date the ISBN system and take longer to enter manually. I realize it will take a long time until I am completely caught up, but it’s a goal I’m working towards. I have barely begun to catalog the e-books on my Kindle as that is not as high a priority but will eventually include them as well.
I’ve loved books all my life and also enjoy organizing (probably should have been a librarian), so making a catalog with the CLZ software is a great fit for me.
In the years I’ve been involved with the CLZ catalog, the software has consistently and vastly improved. Many of my books are rather obscure, but more and more of them are recognized in the enormous CLZ database and come in with many of the fields populated and with the cover photo. Previously I had to take my own photos of some of the book covers and upload them, and those photos don’t come out perfectly, but now most of the books come in with the cover when I enter the ISBN or can be found on the “search the internet” feature. More and more information about the books is now included, so that my catalog is an amazing resource.
The CLZ company is extremely responsive when I have contacted them with a question. I don’t know how large or small the company is, but I get a personal response to my emails. I feel confident that they will help me with any catalog questions, and I have a very positive view of the company.
I recommend CLZ Books Web and Mobile to anyone who wants to make a beautiful and useful book catalog. You will be able to sit and scroll through your library and remember books you might not have focused on for some time. You will be able to enjoy looking at the covers of the precious books you have collected and be happy you have them. You will feel organized and be able to locate books in your home. You will have fun with your catalog if you’re anything like me! I even told our local branch librarian about CLZ for his own book collection.
I have the mobile version as well, for several reasons. Sometimes when I’m in a bookstore, I am not sure whether I already bought a certain book or not; I can tell it is a title I would have liked to own, but I can’t remember if I actually bought it. At least twice I bought a book I already had. Now I can check my mobile catalog. When I finish reading a book, it is quicker to enter that on the “read” field on my phone than to remember to record it next time I am on my catalog on the computer. I can also stand in front of a bookcase with my phone and check whether all the books are cataloged and whether the location is correct.
Beyond practical reasons, I just love having my books organized and cataloged for mental clarity and the pleasure of looking at the titles and covers on the screen. I had once thought of making my own database of my book collection, but it wouldn’t have been nearly as sophisticated as the CLZ one and wouldn’t have included photos of the book covers. Some of my large categories, such as art books, children's books, and Christmas books, have beautiful colorful covers which are a pleasure to look through on the CLZ catalog. I used the genre field to make up my own categories, many of which are not actually genres but the subjects that are important to me. I love that the CLZ software keeps track of the numbers in each category, so for example I know that at the moment I have 184 art and design books, 248 architecture and interiors, 169 autobiography/memoirs, 102 tea books, 213 on England, 206 on New England, 235 children’s books, and 175 Christmas. It’s just interesting to me to know this. It’s a picture of my interests.
So far I have cataloged 2300 of my books. I really enjoy working on the catalog, but it takes time and not all of my books are easily accessible. My method is to scan my new books right away with the app on my phone that CLZ provides, then add them into the collection when I have time to sit at the computer. Then I go to the backlog of older books as I have time and add them in. Some of the oldest ones pre-date the ISBN system and take longer to enter manually. I realize it will take a long time until I am completely caught up, but it’s a goal I’m working towards. I have barely begun to catalog the e-books on my Kindle as that is not as high a priority but will eventually include them as well.
I’ve loved books all my life and also enjoy organizing (probably should have been a librarian), so making a catalog with the CLZ software is a great fit for me.
In the years I’ve been involved with the CLZ catalog, the software has consistently and vastly improved. Many of my books are rather obscure, but more and more of them are recognized in the enormous CLZ database and come in with many of the fields populated and with the cover photo. Previously I had to take my own photos of some of the book covers and upload them, and those photos don’t come out perfectly, but now most of the books come in with the cover when I enter the ISBN or can be found on the “search the internet” feature. More and more information about the books is now included, so that my catalog is an amazing resource.
The CLZ company is extremely responsive when I have contacted them with a question. I don’t know how large or small the company is, but I get a personal response to my emails. I feel confident that they will help me with any catalog questions, and I have a very positive view of the company.
I recommend CLZ Books Web and Mobile to anyone who wants to make a beautiful and useful book catalog. You will be able to sit and scroll through your library and remember books you might not have focused on for some time. You will be able to enjoy looking at the covers of the precious books you have collected and be happy you have them. You will feel organized and be able to locate books in your home. You will have fun with your catalog if you’re anything like me! I even told our local branch librarian about CLZ for his own book collection.
Reviews from customers
Jul 27, 2025
Home Library
I have been thinking about cataloguing my books for years but the daunting task always stopped me from doing so. I then came across CLZ and thought I would give it a try. I was very impressed at the ease at which I could enter books and the speed using ISBN bar code. I also found the App flexible to be able to add obscure books and very old books.
Very pleased and I even enjoyed the experience of adding books. It suited my requirements and much more.
Very pleased and I even enjoyed the experience of adding books. It suited my requirements and much more.
Jul 5, 2025
Excellent
A great app to organize your books, especially if you own hundreds of them. The ISBN scan feature works wonderfully and helps to quickly bring in new books. Highly recommended.
Jun 25, 2025
Absolutely love this app
Allows me to keep track of my books, which ones I have read, how I rated them, which location in the house I can find it. The team have made some great improvements such as reading the ISBN number when there is no barcode. Well worth the yearly subscription.
May 25, 2025
A pleasure to document a library!
The clz team is so thoughtful and helpful, if you have any questions they are available! I have quite a large collection, and this app makes it so so so easy to log everything. their database is extensive, and the isbn scanner is magical! im so happy this app exists, I can stop buying doubles (sometimes triples) by searching my collection before I buy a book! its been so cool to see my collection grow!
Feb 24, 2025
Astonishingly good
CLZ Books is the most wonderful piece of software, enabling me to keep track of my library. Loading new books is made easy through use of ISBN recognition, and the editing and display options are easy to operate and comprehensive. The owners and software engineers must be congratulated on producing a really astonishingly good product.
Feb 11, 2025
I'm quite impressed with CLZ books
It is well thought out and easy to use. Having entered over a thousand books thus far, the ISBN and author/title searches generally work very well. Data can be simply edited as needed. The ability to search and also add tags to books is very handy. The cloud syncing makes it easy to move between an Android phone and an iPad. I've tried a number of times to organize our books with other S/W, but this is definitely the best I've used.
Nov 23, 2024
Excellent app!
My partner and I have been using CLZ Books to organize our 1,000 plus library since the beginning of November. The upgrade with ISBN character recognition gave us an huge boost just as we were beginning to bog down. The whole app is just wonderfully done. We sent a question to support one evening and had the clear answer the next morning.
Apr 26, 2024
Easy to use
I love that I can inventory all my books in one location and sync them to the cloud! Easy to use and add all my books quickly, especially if they have an ISBN. Some of my really old books take longer to add since they don't have an ISBN to type in but it still doesn't take long to add them to the book database. Hopefully, when I am adding them it may help other people to find those books in the future. Of course the ones I'm adding are really really old and probably aren't many of them left.
Mar 16, 2024
The best cataloguing application
This is the best cataloguing application and the mobile version is a god send with the ability to scan ISBN bar code.
Jan 12, 2024
As advertised
Thank you for allowing me to spin the pie chart at the bottom of the statistics page - 10/10 app, does as advertised, my only suggestion would be to add a more satisfying beep sound when you scan an isbn:)
Sep 2, 2023
Facilidade
Facilidade em adicionar livros manualmente e por ISBN Facilidade em filtrar livros por qualquer característica.
Sep 1, 2023
Exceptional book database!!
I have used this program for over 4 years now! Works immediately after downloading and networks with the current ISBN database. Responsive customer service is another plus. IMHO it’s the best book cataloguing app out there!
Apr 8, 2023
There is no easier way than to use this app
I have been using the CLZ apps since they came out in 2019, but I have been using the desktop program since 2002! If you want to catalog your books, there's no easier way than to use this app. It allows you to enter an ISBN and finds the book details for you to add to your collection. You can add further details, etc. You can also assign it as "In Collection", "Wishlist", "On Order", etc. When I go to a bookshop, I can see my wishlist! If you have the desktop app, you can sync back and forth!
Jan 3, 2023
Helpful app
Looks good and works brilliantly! Just add books by isbn works great and if a book hasn't been added you can do that yourself and that's pretty easy too. What I especially like is there are two different coverviews. Option one; everything is boxed in and looks very near, the other option has the same height for every book, so wider books will be displayed large as well.
Oct 25, 2022
Great program and service
I was using this app to catalog the 4000 books in my collection. After about 1000 bucks I upgraded to an iPhone 14. It turns out that the camera on the iPhone 14 will not properly scan the barcode. I contacted the developer and they immediately got back to me. They kept me informed of the progress of the upgrade. They have subsequently fixed the problem and the app works fine now.
The app itself is particularly useful if you have books published after 1967 - you can just scan the ISBN code. You have to manually enter the name of pre-ISBN books, but usually the database that the app is connected to will have some of the information. You can then incorporate that information into your collection database.
The app itself is particularly useful if you have books published after 1967 - you can just scan the ISBN code. You have to manually enter the name of pre-ISBN books, but usually the database that the app is connected to will have some of the information. You can then incorporate that information into your collection database.
Oct 13, 2022
Good
ISBN code scanning works nicely, very helpful.
Sep 15, 2022
Great product
First up - really impressed with the rapid response from tech support - it
was much appreciated (how to add multiple authors to a book).
I've been using BookDB, which has been great, but remembering to export to txt and then copy to my phone so that I didn't buy duplicates in the 2nd hand book stores was getting tedious (you may have noticed I have a lot of pre-ISBN books). So the search was on for something that would allow me to maintain a sufficiently comprehensive database on my laptop and sync it to my phone with minimal effort. Your team has delivered.
Mapping fields between BookDB and Book Collector took a bit of trial and error (mark all as Skip Field, then go back and set correctly) and there are a number of notes I'll have to port manually (eg first edition/signed by author/family connection, austerity printing c WW2, condition of binding etc), but all in all, this is a great product - and the cost is extremely reasonable - I've definitely spent more than that on a single book, so the potential saving in avoiding duplicates is real!
I've been using BookDB, which has been great, but remembering to export to txt and then copy to my phone so that I didn't buy duplicates in the 2nd hand book stores was getting tedious (you may have noticed I have a lot of pre-ISBN books). So the search was on for something that would allow me to maintain a sufficiently comprehensive database on my laptop and sync it to my phone with minimal effort. Your team has delivered.
Mapping fields between BookDB and Book Collector took a bit of trial and error (mark all as Skip Field, then go back and set correctly) and there are a number of notes I'll have to port manually (eg first edition/signed by author/family connection, austerity printing c WW2, condition of binding etc), but all in all, this is a great product - and the cost is extremely reasonable - I've definitely spent more than that on a single book, so the potential saving in avoiding duplicates is real!
May 6, 2022
Keep up the good work guys!
This app takes a bit if getting used to at first, but the catalogue is extensive, and most bar codes and isbn numbers can be used to autofill a good chuck of a collection.
May 1, 2022
Was hesistant due to cost, totally worth it
Very impressive database. It's been able to recognize various pre barcode books with no problem based on isbn.
Feb 26, 2022
Book Collectorz is one amazing application!
I've been using it now for a few years to manage a 1000 book library collection for my quilt guild. What I really love is that the Collectorz team is constantly making improvements to the app that make it easier and faster for the user to manage their collection. The team is responsive and genuinely interested in what their users have to say about the program. The app is simple to use, and very intuitive. You can slice and dice your collection in any way you want to see what you have, and there are a lot of customizable fields if you have specific interests. The connection to "core" is flawless, and simply by putting in the ISBN from the back of a book you get all the information you need in seconds. The price is very reasonable for the value you get from this app.
While I haven't used their other products, I'm sure they are just as refined and useful. Thank you CLZ team, great job!
While I haven't used their other products, I'm sure they are just as refined and useful. Thank you CLZ team, great job!
Dec 16, 2021
Me gusta
El uso simultáneo con el mac y el iphone me da mucha flexibilidad, aunque es más completa la batería de datos del programa para mac.
Sencillo de usar, el escaneo de isbn (hay algunos que aún no localiza) es de lo mejor para obtener datos rápidamente.
Dec 9, 2021
Accurate and user-friendly
This is an excellent app that provided me with the means to create a decent inventory of a small school library. It is very accurate and user-friendly and I am able to create new titles, link existing ISBN's and access my numbers instantly. Highly recommended.
Sep 20, 2021
Like a Personal librarian, great support!
I have been in the process of moving house and clearing out a family storage unit, thrilled with the books I’m finding, remembering and hoping to organize them all into a great library. I was seriously thinking of hiring a librarian to help me with all this when I found this fabulous app. I am able to seamlessly add volumes by isbn numbers and have manually added obscure volumes, photographing the covers and noting their particular histories.
I have been so eager with the newly discovered app, trying to get up to speed, I quickly asked support for some features that I subsequently discovered on my own. I was pleased to get an equally quick answer to my query— how to print out my lists— and can’t wait to do more. I may still hire someone to help me but with this app I am assured that even a student will be able to do a thorough, professional organizing of my library.
Bravo! Six stars!
I have been so eager with the newly discovered app, trying to get up to speed, I quickly asked support for some features that I subsequently discovered on my own. I was pleased to get an equally quick answer to my query— how to print out my lists— and can’t wait to do more. I may still hire someone to help me but with this app I am assured that even a student will be able to do a thorough, professional organizing of my library.
Bravo! Six stars!
Aug 10, 2021
Great book catalogue
Love working with this app. Books can be entered by scanning their barcode, so it’s a powerful bookcataloguing system that’s very quick and easy to use. I make heavy use of options that allow you to personalize the settings and stored details, so it’s tailored to my needs.
Over the 7 years that I’ve used this app, I’ve seen lots of improvements. The developers are in-tune with their customers—if we ask for new functionality, it’s actually considered and often implemented. I even had the owner email me when I had an issue!
Over the 7 years that I’ve used this app, I’ve seen lots of improvements. The developers are in-tune with their customers—if we ask for new functionality, it’s actually considered and often implemented. I even had the owner email me when I had an issue!
Jun 2, 2021
Excellent app
An excellent app which is very sophisticated and powerful. A delight to use and Cloud synchronisation is a major asset as is the camera based ISBN scanning and adding feature.
Jun 1, 2021
Very Handy!
If you are a book collector (a bibliophile!) then at a certain point you can’t keep an accurate track of your collection in your head. This becomes a problem when you are in a book store, you see something interesting and you really should know if you already have that book, or that particular edition or if the asking price is a bargain or too high. CLZ Books on the iPhone is a perfect way to keep track of not only what you have in your collection but also what is on your “want list” with lots of details. Using a book’s ISBN code, CLZ Books will fill in most of the critical data, including an image of the cover, and it is quite easy to add the missing pieces that are important to you (date of purchase, which bookstore, etc.). All this information sitting there sitting in your phone ready to be tapped into on a moment’s notice. I’ve been a CLZ customer for many years, starting when only a PC version was available. I didn’t choose their program lightly. It was just the best one available at the time. Their constant improvements and their expansion into the Mac world and then onto the iPhone has confirmed that my early adoption was valid and I still am a total fan of their app and believe that the price is a bargain for the product and the service.
May 30, 2021
Fantastic software for bookaholics - and clubs
I have used the book cataloging software for many years to catalogue the many (many) books we have stored in numbered boxes and bags in our loft. I had also catalogued the books belonging to our local Embroidery group.
We wanted to make full use of the group’s books during lockdown and with the superb help of the Collectorz support team, we set up a separate Library and included, on separate sheets, books belonging to members who were willing to loan them out. Until face-to-face meetings resume, we have an ad hoc doorstep delivery system in place, supported by the Loan facility within the software.
The CLZ Barry scanner enables members to scan the barcodes of books they are willing to loan and email the ISBN numbers directly from the App to our Librarian for logging. Subject to Covid restrictions, we can work directly with any member who has as many books as me, to load the books directly. It is particularly helpful to be able to sort on technique, subject etc as well as author and title.
The software works and the support team are easy to contact and really helpful. Highly recommended!
The CLZ Barry scanner enables members to scan the barcodes of books they are willing to loan and email the ISBN numbers directly from the App to our Librarian for logging. Subject to Covid restrictions, we can work directly with any member who has as many books as me, to load the books directly. It is particularly helpful to be able to sort on technique, subject etc as well as author and title.
The software works and the support team are easy to contact and really helpful. Highly recommended!
May 27, 2021
Perfect for Organizers!
I love to organize and as a homeschool mom I have nearly 1,000 books. Keeping them organized would be such a chore but this app makes it so easy! I love being able to scan the ISBN of a book to add it to my booklist. And pro tip: if you have lots of older books with no barcode, I’ve found the fastest way to enter them is to go to the keyboard for typing it in, and then click on my microphone and quickly say the numbers. Works great!
May 20, 2021
Great Book inventory product
I own over 540+ books and this does a nice database job. I buy a lot of HISTORY books and computer books, this works great to prevent duplicate purchases. When looking at new wish books like the wish list for recall when asked for gift ideas. Like the detail and the book cover pic to compare if purchase or already own. Easily search when shopping especially mobile.
Alwin & Team constantly adding new features
Via enhancement updates. If there is a problem
The Team addresses it very quickly although i have owned for many years and haven’t found too many issues mostly just added enhancements. Highly recommend, cost effective and enjoy it so much purchased several other of his inventory products.
Couldn’t add to collections without this product
And adding via Title or even better ISBN code is great. App is flexible and allows for cover graphics override so can match exact ownership version. Highly enjoy & Recommend.
Apr 25, 2021
A joy to use
I have really enjoyed the use of your products over the years. The Books and Comics in particular made cataloging my collections a whole lot easier to finish and sort. It was really nice that I was able to add most items without having to enter each piece of data separately, like some of the other software out there.
What seemed like an endless task of adding 3500+ paperbacks and hardcover, became a joy to do. The use of a barcode reader just made it that much faster. I still had to manually input a fairly large number of books as they were printed before the barcode system came into being, but even that, for the most part, was reasonably easy to do by using the ISBN. A bit tougher to enter the ones without any ISBN listed, but there the search by title and author made things doable.
What seemed like an endless task of adding 3500+ paperbacks and hardcover, became a joy to do. The use of a barcode reader just made it that much faster. I still had to manually input a fairly large number of books as they were printed before the barcode system came into being, but even that, for the most part, was reasonably easy to do by using the ISBN. A bit tougher to enter the ones without any ISBN listed, but there the search by title and author made things doable.