WorldCat is a global union catalog operated by OCLC that connects you to collections from over 10,000 libraries in 123 countries. You can search more than 500 million bibliographic records to find books, journals, and media, then locate copies available near you.
What Is WorldCat?
WorldCat functions as a union catalog—a combined database that shows holdings from thousands of libraries in a single search interface. The Online Computer Library Center (OCLC) operates WorldCat as a cooperative service where member libraries contribute their catalog records to create the world’s most comprehensive bibliographic database.
The system includes records from academic libraries, public libraries, national libraries, and special collections across 123 countries. As of 2024, WorldCat contains over 500 million unique records representing more than 3 billion physical and digital items.
You can access WorldCat for free through WorldCat.org. The public interface lets anyone search the database and identify which libraries hold specific materials. Libraries also use professional versions like WorldCat Discovery and WorldCat FirstSearch that offer additional features for institutional users.
The cooperative model means libraries share cataloging work and resources. When one library creates a detailed record for a book, other libraries holding that same book can use that record rather than duplicating the effort.
How WorldCat Works
Each item in WorldCat has a bibliographic record—a structured description containing the title, author, publication details, subject headings, and physical description. Libraries following standardized formats (primarily MARC) create these records, which ensures consistency across the database.
When you search WorldCat, the system queries all contributed records simultaneously. Results show you which specific libraries own the item you’re looking for. Each result displays the number of libraries holding that item and their geographic locations.
WorldCat doesn’t provide direct access to materials. Instead, it acts as a discovery tool that points you toward libraries where items physically exist. You’ll see location information based on your zip code, with nearest libraries listed first.
The system updates continuously as libraries add new acquisitions and remove withdrawn items. This real-time updating means you’re seeing current holdings information, though you should always verify availability directly with the library before visiting.
Who Uses WorldCat
Students use WorldCat to locate materials their home institution doesn’t own. When writing research papers or theses, you can identify relevant books at nearby universities and arrange interlibrary loans or visitor access.
Researchers rely on WorldCat for comprehensive literature searches. The database includes scholarly monographs, dissertations, conference proceedings, and rare materials that don’t appear in article databases or search engines.
Public library patrons search WorldCat to find items their local branch doesn’t carry. Many public library systems participate in resource-sharing networks, so librarians can request materials from other WorldCat libraries on your behalf.
Genealogists and historians use WorldCat to locate primary sources, local histories, and archival materials. The database includes records for microfilm collections, historical newspapers, and manuscript collections held by historical societies and archives.
Librarians use WorldCat daily for cataloging, interlibrary loan processing, and reference work. The professional interfaces provide copy cataloging services and streamlined request management.
How to Search WorldCat
Basic Search
The WorldCat.org homepage provides a straightforward search box with format tabs. You can restrict your search to books, articles, audiovisual materials, or search all formats simultaneously.
Enter your search terms—title, author, subject, or keywords. The system searches across all record fields by default. For books, entering just the title or author typically produces manageable results.
Format filters appear as tabs above the search box. Click “Books” before searching if you only want monographs, or “Music” for audio recordings. This pre-filtering saves time compared to sorting through mixed results.
You don’t need an account to search. WorldCat.org is publicly accessible, though some libraries require authentication to access their institutional WorldCat Discovery interfaces.
Advanced Search
Click “Advanced Search” below the main search box to access multiple search fields simultaneously. You can combine title, author, subject, ISBN, and other fields with Boolean operators.
The advanced interface includes dropdown menus for material type, language, publication year range, and audience level. Searching for books published in French between 2010-2020 takes just a few clicks.
ISBN and ISSN searches work particularly well when you have a specific citation and need to locate holding libraries. Enter the 10- or 13-digit ISBN to find exact editions rather than sorting through multiple versions.
Publisher searches help when looking for series or materials from specific university presses. Combine the publisher with subject terms to narrow results to relevant scholarly works.
Refining Your Results
After searching, use the left sidebar facets to narrow results. You can filter by publication year, language, format, author, and content type without starting a new search.
The publication year slider lets you focus on recent materials or historical works. Moving the slider dynamically updates results, showing you how many items fall within each timeframe.
Sorting options include relevance, date (newest or oldest first), and library holdings count. Sorting by holdings shows you which items are most widely available, making them easier to obtain through interlibrary loan.
Result previews show the title, author, publication year, and format. The number of libraries holding each item appears below the title. Items held by 1,000+ libraries are typically recent popular books or classic texts.
Finding Items Near You
Enter your zip code in the location box on any results page. WorldCat reorganizes the library list to show the nearest locations first. You’ll see distances in miles or kilometers depending on your region.
The library list for each item shows institution names, cities, and collection information. Some libraries specify floor locations or call numbers, helping you locate materials once you arrive.
Availability status varies by library. Most records show only that a library owns the item, not whether it’s currently checked out. Call the library or check their online catalog for real-time availability before visiting.
Different libraries have different access policies. Academic libraries often allow community members to use materials on-site but restrict borrowing privileges. Public libraries typically require a library card for checkout, which may involve residency requirements.
What WorldCat Can and Cannot Do
WorldCat excels at locating physical materials held by libraries worldwide. If a book exists in any participating library, WorldCat will show you where to find it. This makes it valuable for tracking down out-of-print books, dissertations, and specialized materials.
The database supports interlibrary loan by identifying potential lending libraries. Your library can search WorldCat to find institutions willing to lend specific items, though WorldCat itself doesn’t process loan requests.
WorldCat helps you assess a work’s significance. A book held by hundreds of libraries suggests it’s considered important in its field. Conversely, items held by only one or two libraries may be rare or specialized.
WorldCat cannot provide direct downloads of ebooks or articles. While records may indicate that electronic versions exist, you’ll need to access those through your library’s subscription services or publisher websites.
The system doesn’t guarantee physical access. A library appearing in WorldCat might have visitor restrictions, closed stacks, or special collections policies requiring advance appointments. Always contact libraries before visiting.
Not every library participates in WorldCat. Some institutions maintain independent catalogs, particularly outside North America and Europe. If you don’t find an item, try searching the specific library’s catalog directly.
WorldCat vs. Other Library Tools
Google Books searches full text and provides preview pages, making it better for finding specific quotes or passages. WorldCat focuses on helping you obtain complete works through libraries rather than offering partial online access.
The Library of Congress catalog covers the national library’s extensive holdings in detail, including materials not widely held elsewhere. For U.S. government documents and specialized historical collections, the LC catalog often provides more detailed information.
Individual university library catalogs show real-time availability and allow you to place holds or requests. Check your home institution’s catalog first for convenience, then use WorldCat to find materials they don’t own.
Amazon and other booksellers help when you’re willing to purchase items. WorldCat helps when you want to borrow or examine materials without buying them.
Use WorldCat when you need comprehensive coverage across many libraries, particularly for scholarly materials, historical works, or items not available commercially. It’s your starting point for serious research requiring materials from multiple institutions.
Tips for Better WorldCat Searches
Start with broad searches using one or two terms, then narrow results using the sidebar filters. Beginning too specifically might miss relevant items cataloged with different terminology.
Use quotation marks around exact phrases. Searching for “climate change policy” finds that specific phrase, while searching without quotes finds items containing all three words anywhere in the record.
Try multiple search approaches. If a title search yields nothing, try the author’s name or subject terms. Different cataloging practices mean the same work might be described in various ways.
Check publication dates when assessing results. The most recent edition of a textbook may be more useful than a 30-year-old version, while historical research might specifically require earlier editions.
Contact libraries directly with questions. If a record seems incomplete or you’re unsure about access policies, phone or email the library. Reference librarians can clarify holdings and help arrange access.
