List of Biggest Libraries of the World-
| Name & Country | Location | Catalogue size |
| British Library, United Kingdom | London and Boston Spa | 170–200 million |
| Library of Congress, United States | Washington D.C. | 170 million+ |
| Library and Archives, Canada | Ottawa | 54 million |
| Shanghai Library, China | Shanghai | 50 million |
| Russian State Library, Russia | Moscow | 47.2 million |
| Royal Danish Library, Denmark | Copenhagen and Aarhus | 42.5 million |
| National Diet Library, Japan | Tokyo and Kyoto | 41.9 million |
| Bibliothèque Nationale de France | Paris | 40 million |
| National Library of China | Beijing | 37.7 million |
| National Library of Russia | Saint Petersburg | 36.5 million |
| German National Library, Germany | Leipzig and Frankfurt | 36.1 million |
| Biblioteca Nacional de España, Spain | Madrid | 33.1 million |
| Library of the Russian Academy of Sciences, Russia | Saint Petersburg | 26.5 million |
| Berlin State Library, Germany | Berlin | 23.4 million |
| Boston Public Library, United States | Boston, Massachusetts | 22.4 million |
| New York State Library, United States | Albany, New York | 20 million |
| Harvard Library, United States | Cambridge, Massachusetts | 18.9 million |
| National Library of Sweden | Stockholm | 18 million |
| Vernadsky National Library of Ukraine | Kiev | 15.5 million |
| Yale Library, United States | New Haven, Connecticut | 15.2 million |
| National Library of Iran | Tehran | 15 million |