6 Best Search Engines for Finding Free PDF eBooks Online

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6 Best Search Engines for Finding Free PDF eBooks Online

Key Points

  • PDFs have become a convenient way to read books, offering access to multiple titles without the need to visit a physical library or store.
  • When choosing a PDF search engine, consider the available genres, additional features, user interface, and semantic search.
  • Internet Archive offers access to more than 39 million books and allows members to upload new files to grow its catalog.
  • Project Gutenberg is one of the oldest digital libraries with over 70,000 free eBooks.
  • Manybooks is home to over 50,000 free eBooks and is a great site for indie books.
  • PDFBooksWorld has a wide variety of genres and subjects and hosts several thousand free eBooks.
  • Z Library has one of the largest eBook catalogs with over 120 million files and allows users to request books that are currently unavailable.
  • PDFDrive has over 84 million free PDF eBooks and offers smart recommendations based on your search history.

Book fanatics can attest that nothing tops the smell of books and coffee in the morning. Reading a book every morning boosts your focus and cognitive function for the day. Unfortunately, the introduction of PDF eBooks has phased out reading physical books. However, eBooks offer invaluable convenience you cannot get with physical copies. You only need to search for the title on your preferred PDF search engine.

Most PDF search engines have filters, making finding the book you want easy. For instance, you can limit the search results based on alphabetical order, author, or publishing year. This saves you a lot of time compared to visiting a physical library or store to get a book. So, after reviewing the options, here are the six best search engines for finding free PDF eBooks online.

History-Computer’s Top Picks for the Best Search Engines for Free PDF eBooks

Internet Archive

.com vs .org
The Internet Archive has millions of free PDF eBooks you can borrow or download.

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Internet Archive currently boasts over 39 million eBooks and texts, which you can access for free. You can also access up to over 15 million recordings, including live concert recordings. The search engine is not difficult to navigate, but there are tens of millions of items, so it can be tricky to locate exactly what you are looking for. If you don’t have a specific title in mind, you can select the “Books” tab at the top of the page. Then enter “PDF” in the search bar and click the button that says “Search this collection.” Make sure to tick the circle for “Search metadata” to return results that have PDF files.

If you know the eBook title you would like to search for, type your keywords into the search box and click “GO.” When the engine returns your results, click on the eBook’s title. Then, search the download options on the right-hand side to see if there is a PDF file available to borrow or download. Alternatively, you can use the advanced search option to narrow the search results. This option allows you to specify the book’s title, publishing date, subject, and volume, among others.

Some search engines aren’t vigilant about updating their catalogs, but Internet Archive addresses this concern. The organization scans 4,300 books daily from 18 different locations. Internet Archive allows members to upload new files to grow its catalog. We were also impressed by Internet Archive’s Wayback Machine. Users can access up to 832 billion web pages, which have been archived over the years.

It offers access to more than 39 million books.It has been criticized for copyright infringement.
The search engine is updated daily.It can be difficult to find exactly what you are looking for.
You borrow some titles if they are unavailable for download.

Project Gutenberg

Search engines PDF Books
Project Gutenberg has over 70,000 free eBooks in its database.

©Postmodern Studio/Shutterstock.com

Launched in 1971, Project Gutenberg is one of the oldest digital libraries. This is unsurprising, considering its founder, Michael S. Hart, was the brains behind the eBook format as we know it today. Project Gutenberg claims to have over 70,000 free eBooks, which its users can read online or download.

Finding a PDF eBook on Project Gutenberg is easy for the most part. The most straightforward option is to type the PDF’s title or related keywords in the “Quick search” bar and click “Go!” The site allows you to sort the search results by popularity, alphabetically, or by release date.

Alternatively, you can use the “Book Search” or “Bookshelves” options. Under the Book Search option, you can opt for Quick Search, Advanced Search, Browsing Options, or Full-Text Search. The Advanced Search option lets you focus your search by providing the book’s title, author, subject, and language, among other metrics. When you find a book you want, click on the image or title, then select PDF from the formats available.

The “Browsing Options” lists books categorized based on authors, titles, languages, special categories, or those uploaded recently. Finally, the “Full-Text Search” option allows you to find available PDFs on Project Gutenberg using Yahoo!, Google, or DuckDuckGo search engines. The Bookshelf feature is very similar to the Browsing Options under Book Search. It comprises free PDFs grouped by subject.

Project Gutenberg also provides a list of frequently viewed or downloaded PDFs, which you can use to find trending books. You can also find free eBooks on Project Gutenberg using its Offline Catalogs and Feeds. However, we found this option the most complicated and recommend using it as the last resort.

The eBooks are categorized by subject.It has fewer books than some sites like Internet Archive, as they only include works in the public domain.
You can download the PDFs or read them online.The Offline Catalogs and Feeds are complicated to understand and use.


Kindle vs iBooks
You can download free indie books in any genre on Manybooks.

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Manybooks is home to over 50,000 free eBooks. The eBooks are categorized into several genres. Examples include Action and Adventure, Bios and History, Fantasy, Historical Fiction, Horror, Literary Fiction, Science Fiction, and more. Manybooks is also a great site for indie books, as they welcome the work of self-publishing authors.

ManyBooks has an easy-to-use search function. You must only type or paste the book’s title, author, or keyword and click the search icon or button. The site usually sorts the search results by popularity. However, you can also sort the results by title, author, or rating. When you find an eBook you want to read, just select PDF from the list of available formats. You can also read online using the PDF viewer on your computer.

To the left of the search results are filters you can use to focus your search. You can filter the search results based on ratings, language, and genre. Input the filters and click “Apply” to refine your search. Besides using the search bar, you can browse the listed catalogs on the homepage to find free eBooks. Some popular categories include Editor’s Choice, Trending Books, and Popular Classics.

ManyBooks offers more than just free eBooks. For example, you may find interviews with your favorite authors under the resources section. The site also has a forum where readers and authors can discuss trending books.

It has an easy-to-use search function.Some eBooks are not available for free.
You can find free eBooks based on genre.
It is a great site to find indie books.
You can download PDFs or read them online.


Kindle Scribe vs. reMarkable
The PDFBooksWorld library offers high-quality PDF eBooks that are in the public domain.


PDFBooksWorld prides itself on providing high-quality eBooks with legible fonts, illustrations, and clickable links. It has a variety of genres and subjects, including fictional, non-fictional, and academic eBooks that are in the public domain.

Unfortunately, the site does not expressly state how many free eBooks it hosts. However, we ran several searches using keywords like “romance,” “history,” and “fiction.” Each search returned at least several hundred results, with some crossing the 1,000 mark. So, it is safe to assume that PDFBooksWorld has at least several thousand free eBooks.

The site does not provide a search bar on its homepage; this was surprising and may put off some users. Instead, you have to click the “Search” button on the top-right corner, or you can also click the button at the bottom of the page that says, “Find your Book To Read Now” to search. Both of these buttons will take you to a new page with the search tool. You can find free eBooks by typing or pasting the title, author, or subject. The site does not have filters to sort the search results, so you may have to manually find the PDF you want.

Alternatively, you can find books by browsing the list of genres, authors, or new and popular books. These categories are provided as menu items at the top of the homepage.

It has a wide variety of genres and subjects.The interface is not as user-friendly as some other sites.
You can browse free PDFs based on author or genre.It does not provide any filters for refining search results.
They only have books in the public domain.

Z Library

epub vs pdf
Registered Z Library users can request books that are currently unavailable on the website.

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Z Library has one of the largest eBook catalogs. It claims to have over 120 million books, tutorials, and manuals and continues to update its repository regularly. You can monitor the real-time file count by checking the search bar at the top of the homepage.

Z Library has one of the simplest search tools. You only need to paste or type the title or the author of the book you want to find and click on the search icon. The search results page has two filters that allow you to sort the eBooks based on the number of pages or publishing year. Z Library allows users to download eBooks without signing up. You may download an eBook as a PDF, EPUB, or MOBI file. However, you must sign up to enjoy some benefits, like saving your search history and bookmarking books to read later.

Besides using the search bar, you can use the subjects or categories listed on the right side of the homepage to find free books. For example, clicking the “Most Popular” category generates a list of the most downloaded books on the website.

Finally, Z Library allows its registered users to request books currently unavailable on the website. You only need to provide the book’s title, author name, language, publishing date, and cover image. You will receive an alert when the eBook is uploaded to Z Library.

It has more than 120 million files.It does not provide enough filters to refine your search.
You can request a book that is currently unavailable on the website.Users must sign up to enjoy benefits like bookmarking PDFs to read later.
You may receive a bad gateway error when you try to download an eBook.


search engines for PDF eBooks
PDFDrive will recommend books for you based on your search history.

©Postmodern Studio/Shutterstock.com

There are over 84 million PDF eBooks available on PDFDrive. The site uses bots and crawlers to scan websites for new PDF eBooks to add to its repository, so they are continually adding new content.

This search engine has one of the simplest user interfaces. For example, you can use the basic or advanced searches when looking for a specific eBook. The advanced search option allows you to filter books by page number, file size, and popularity. You can also explore the available eBooks by topic, as they are categorized by genre.

We were impressed by this search engine’s smart recommendations feature as well. It suggests other PDF eBooks related to your topic based on your search history. Also, you can accept to receive weekly notifications of all the trending eBooks related to your topic.

They have over 84 million eBooks you can download for free.It has been criticized for allowing pirated content.
The eBooks are classified by topic.
It recommends books based on your search history.

Choosing the Best PDF Search Engines: Step by Step

Now, let’s discuss some factors to remember when choosing the best search engines for finding free PDF eBooks online.

  • Available genres
  • Additional features
  • User interface
  • Semantic search

Available Genres

The search engine you choose should suit the type of book you want to find. Otherwise, you may spend a lot of time searching for the book and not finding it. For example, suppose you are trying to find a free PDF of your favorite romance novel. You should use a search engine with romance as one of the available genres or sub-categories. Searching for the book on a site that focuses on comics and action-adventure may be counterproductive.

Additional Features

A good search engine offers more than just the search tool and filters. It should offer additional features like smart recommendations and alerts. Some search engines like Manybooks also offer forums where readers and authors can discuss trending books. Finally, opt for a search engine that allows users to review the eBooks they’ve read. This is helpful when sifting through PDFs, as you can limit your search to the highest-rated eBooks.

User Interface

A search engine’s user interface influences your overall experience. Choose a PDF search engine that is user-friendly. The website should be well-organized and easy to navigate. For example, the search tool should be visible. It should also be easy to use the advanced search option. Since some search engines offer more than one eBook format, ensure you can easily locate PDF files for download.

Opt for a PDF search engine with semantic search, especially when finding eBooks using keywords. This feature allows a search engine to make sense of your keywords and return the most probable search results. It leverages the perceived search intent and context to deliver relevant results.

This is handy should you use the wrong keywords or make typing errors that alter the keywords. For instance, suppose you search the keyword “Fity Shades” instead of “Fifty Shades;” the PDF search engine will query its databases using the right spelling.


PDFs have become a convenient way to read books. You only need a smartphone and a good search engine offering free PDF eBooks. You will enjoy the convenience of accessing multiple books without visiting a library or local bookstore. PDF eBooks also eliminate the hassle of carrying physical books.

However, you ought to use the right search engine to access the free PDFs. Compare different search engines to choose one with diverse genres. Also, opt for a search engine that is easy to use and navigate. This will save you the time you would otherwise waste trying to figure out how to use the search tool or advanced search option.

Frequently Asked Questions

Which is the best search engine for free PDF eBooks for students?

Internet Archive is arguably the best search engine for free PDF eBooks. It provides access to over 39 million PDFs. It also has an expansive Wayback machine offering more than 832 billion web pages.

What’s the main advantage of using search engines for PDF eBooks?

Search engines for free PDF eBooks guarantee quick access to reading material in your chosen format. Some search engines also allow users to bookmark or save PDFs to read later. 

What should you consider when choosing which search engine to use for free PDF eBooks?

Consider the search engine’s user interface and search function. For example, the search bar should be easy to find on the homepage. The site should also provide filters to focus and refine the search results.

Which is the best search engine for free PDF eBooks for students?

Internet Archive stands out as the best overall search engine for students and non-students alike. You can access more than 39 million PDFs and 832 billion web pages.

Will I be charged a fee to access the PDF eBooks?

Yes and no. Most search engines offer PDF eBooks for free. However, some sites may charge you a fee to read or download specific PDFs or to access additional features.

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