A few years ago, our small team at Affor Technologies hit a wall that many readers know too well. We needed to convert a handful of EPUB textbooks into PDFs for printing, and every free tool we tried demanded that we upload personal files to some distant server. One tool even asked for an email address before we could download the result. We looked at each other and asked: why does converting a file require trusting a stranger with your documents? That question led us to build CheersPDF — a converter that runs entirely inside your browser. Your EPUB, MOBI, and PDF files never leave your device. There is no server to send them to, no account to create, and no limit on how many files you convert.
Three steps from start to finish. No account. No file upload. Your books stay on your own device the entire time.
Choose an EPUB, MOBI, or PDF file from your device, or drag and drop it onto the page. We accept files up to 100 MB — enough room for even the longest novel or a heavy textbook packed with diagrams. Most ebooks are well under 10 MB, so conversions usually finish before you can blink.
Your file is processed entirely inside your browser using a technology called Web Workers — background threads that handle the heavy lifting without freezing your screen. The converter reads the file, parses each chapter, preserves images and headings, and generates the output format you need. If you are curious about the engineering behind this, we wrote a deep dive on our conversion pipeline.
Your converted file downloads automatically — clean, well-formatted, and ready to use. Whether it is a PDF for printing, an EPUB for your e-reader, or a ZIP of extracted images, the output is designed to look great on any device. Once the download finishes, nothing remains in the browser. The file goes straight to your device and nowhere else.
We built this tool because we needed it ourselves. Every design decision reflects a specific frustration we experienced with existing converters.
Most converters promise privacy in their terms of service while uploading your files to servers you cannot audit. We took a different approach entirely. CheersPDF has no file-receiving server — there is literally no infrastructure that could accept your documents, even if we wanted it to. Your files are processed in the browser sandbox, the same isolated environment that protects your online banking sessions. When people ask "is my file really private?", we can answer with certainty: yes, because there is nowhere for it to go.
Because there is no network round trip — no upload, no queue, no download — most files convert in under ten seconds, even on a mid-range laptop or phone. Web Workers process the file in a parallel thread so your browser tab stays responsive while the conversion runs. There are no "you are number 47 in line" messages and no spinning wheels while a server catches up. The speed difference between local and cloud conversion is not marginal; it is dramatic.
Once the page has loaded, CheersPDF works without an internet connection. This makes it genuinely useful during flights, on trains, or in rural areas where connectivity is spotty. We have heard from teachers in remote schools and traveling professionals who rely on this feature regularly. You do not need to install anything — the converter runs in whatever browser your device already has.
We intentionally designed CheersPDF without accounts, logins, or email verification. We believe tools should be accessible to everyone without asking for personal information in return. Many converters use sign-up walls as a way to collect marketing data. We chose not to. Just open the page, select your file, and you are done.
Our converter does not simply dump raw text into a PDF. It preserves chapter structure, headings, page numbers, and embedded images. The result reads like a properly formatted document, not a hastily generated file. We regularly test output quality against popular desktop applications like Calibre and Adobe Acrobat to make sure the result meets professional standards.
In late 2024, our co-founder was preparing study materials for an exam. He had a collection of EPUB textbooks that needed to be printed as PDFs. The first converter he found uploaded his files to an unknown server and then asked him to wait in a queue. The second converter added a watermark to the output and demanded payment to remove it. The third one actually worked but required creating an account and sharing his email address.
He mentioned the experience to the rest of our team at Affor Technologies, and that conversation turned into a question none of us could shake: if modern browsers can run complex games, edit videos, and process spreadsheets, why can they not convert an ebook locally?
It turns out they can. The browser runtime supports Web Workers for parallel processing, the File API for reading local files, and well-established libraries like jsPDF for PDF generation and JSZip for archive handling. We spent weeks building the first version of CheersPDF, tested it on hundreds of ebook files, and launched it as a free tool.
Today, CheersPDF supports four conversion tools — EPUB to PDF, MOBI to PDF, PDF to EPUB, and PDF Image Extraction — all running entirely in the browser. We use it ourselves every day, and we are committed to keeping it free and continuing to improve it. The site is supported by advertising, which allows us to provide every feature at zero cost to every user. If you would like to know more about the team, our principles, and how we think about privacy, visit our About page.
Not sure which format you need? Here is a plain-language overview of the formats CheersPDF works with — and when each one makes the most sense.
EPUB stands for Electronic Publication. It is an open standard maintained by the W3C, and it is supported by almost every e-reader, tablet, and reading app outside of the Kindle ecosystem. The defining feature of EPUB is reflowable text: the content adjusts to fit your screen, whether you are reading on a six-inch e-reader or a 27-inch monitor. Most public libraries, independent bookstores, and DRM-free publishers distribute ebooks in EPUB format. If you own a Kobo, Nook, or use Apple Books or Google Play Books, EPUB is your native format.
The MOBI format was originally created by Mobipocket, a French company that Amazon acquired in 2005. Amazon built the Kindle ecosystem around MOBI (and its close variant PRC), making it the default format for millions of Kindle users. While MOBI served readers well for over a decade, it is a closed format with limited compatibility outside of Amazon devices and apps. Amazon has since shifted to newer formats like AZW3 and KFX, but millions of older ebooks and personal documents remain in MOBI format. Converting MOBI to PDF or EPUB frees those books from Kindle lock-in.
PDF, or Portable Document Format, was created by Adobe in the 1990s and is now an ISO-standardized format. Unlike EPUB, PDF uses a fixed layout — every page looks identical regardless of the device or printer. This makes PDF the go-to format for printing, sharing formal documents, academic submissions, and long-term archiving. The trade-off is that PDFs can be difficult to read on small screens because the text does not reflow. That is exactly why converting a PDF to EPUB can dramatically improve the reading experience on phones and e-readers.
For a deeper comparison, read our guide on EPUB vs PDF: What's the Difference and When Should You Convert?
We built CheersPDF as a general-purpose converter, but we have been genuinely surprised by the range of people who find it useful. Here are some of the most common ways people use it.
Many students receive textbooks in EPUB format from university libraries or open educational resource platforms. When they need to annotate, highlight, or print specific chapters, converting to PDF gives them a format that works with tools like Adobe Acrobat, Kami, or even the built-in PDF viewer on their laptops. We hear from students every week who tell us CheersPDF saved them from buying an expensive software license.
Authors who publish on platforms like Amazon KDP often need to create PDF review copies for editors, beta readers, or literary agents who prefer a fixed-layout document. CheersPDF lets them convert their EPUB manuscript into a professional PDF in seconds — without uploading sensitive intellectual property to a third-party server.
Teachers who curate reading materials from open-access publishers frequently need to convert ebooks to PDF for classroom distribution. Since many school networks block file-upload sites for security reasons, a browser-based converter that does not upload anything is often the only practical option available to them.
Academic papers and monographs are often distributed in PDF format, but researchers increasingly want to read them on e-readers during commutes or conferences. Converting PDF to EPUB makes those documents reflowable and far more comfortable to read on a Kindle or Kobo — especially for long reading sessions.
Digital librarians sometimes need to convert ebook collections between formats for cataloging, archival, or patron access purposes. PDF is an ISO-standardized preservation format, so converting EPUB to PDF is a common step in long-term digital archiving workflows.
Some people simply prefer not to upload personal reading materials to servers they do not control. Whether the concern is data retention, surveillance, or simple preference, CheersPDF provides a verifiable guarantee: your files physically cannot leave your device because there is no server to receive them.
Each tool is purpose-built for its specific conversion. Choose the one that matches your needs.
Convert EPUB ebooks to clean, well-formatted PDF files with preserved chapters, headings, page numbers, and embedded images. Ideal for printing, sharing, and archiving books in a universally readable format that looks the same on every device.
Convert NowFree your Kindle MOBI and PRC files from format lock-in. Convert them to universally readable PDFs with chapter preservation and clean text extraction. Perfect for reading Kindle books on non-Amazon devices or printing personal copies.
Convert NowTurn rigid PDFs into reflowable EPUB ebooks with smart chapter detection and image extraction. Read your PDFs comfortably on any e-reader, phone, or tablet — with text that adapts to your screen size instead of forcing you to zoom and scroll.
Convert NowExtract all images from one or multiple PDFs and download them as an organized ZIP archive with chapter-based folders. Supports PNG, JPEG, and SVG output formats. Ideal for designers, educators, and anyone who needs to repurpose visual content from documents.
Extract ImagesYes, completely free. There are no premium tiers, no daily limits, no watermarks on output files, and no hidden charges. We built CheersPDF because we needed a good converter ourselves, and we decided to share it openly. The site is supported by advertising, which allows us to keep every feature available to every user at zero cost. We do not gate features behind paywalls and we do not plan to.
No, and this is not just a policy promise — it is an architectural fact. When you select a file, your browser reads it locally using the JavaScript File API. The conversion happens entirely on your device: parsing chapters, extracting images, generating the output. Nothing is uploaded, stored, or transmitted to any server. We built CheersPDF without any file-receiving server infrastructure, so your documents literally have nowhere to go but your own device.
CheersPDF is built and maintained by Affor Technologies, a technology company focused on building privacy-first tools for everyday use. We are a small team of developers and readers who believe that common utilities like file converters should not require you to sacrifice your privacy or pay a subscription. You can learn more on our About page or reach us at contact@affortechnologies.com.
Yes. Once the page has loaded in your browser, CheersPDF works completely without an internet connection. You can convert files during flights, on trains, or in areas with unreliable connectivity. The entire conversion engine runs locally in your browser, so no server communication is needed after the initial page load. This is one of the practical advantages of browser-based processing over cloud-based alternatives.
CheersPDF supports files up to 100 MB each, which covers the vast majority of ebooks and documents. Most ebooks are between 1 MB and 10 MB. Even image-heavy textbooks and illustrated novels typically fall well within the 100 MB limit. If you have an exceptionally large file, it may take longer to process depending on your device's available memory and processing power — a desktop computer will handle it faster than a phone.
CheersPDF works in all modern browsers: Google Chrome, Mozilla Firefox, Microsoft Edge, Safari, and Opera. It is fully responsive and works on desktop computers, laptops, tablets, Chromebooks, and mobile phones. For the best experience, we recommend using the latest version of your preferred browser. On mobile devices, very large files may take longer due to hardware differences, but the conversion will still complete successfully.
No. Files that are protected with DRM (Digital Rights Management) cannot be converted by CheersPDF or any other legitimate converter. DRM is a technology that restricts how a file can be used, and we respect those restrictions. CheersPDF works with DRM-free ebooks — those purchased from DRM-free publishers, downloaded from public domain libraries like Project Gutenberg, or personal documents you have created yourself. If you are unsure whether your file has DRM, our guide to DRM explains how to check.
In-depth guides, format comparisons, and practical tips to help you get the most out of your ebook collection.
A step-by-step walkthrough of browser-based ebook conversion. We explain how the technology works, why it is safer than cloud-based alternatives, and how to get the best output quality from your EPUB files.
Read GuideBoth formats have their strengths. We break down when EPUB wins, when PDF wins, and when it makes sense to convert between them — with practical examples for readers, students, and professionals.
Read GuideAn honest comparison of the top free converters available today. We evaluate each tool on privacy, output quality, format support, and ease of use — including a candid assessment of our own strengths and limitations.
Read GuideEverything you need to know about the major ebook formats: their origins, what each format does best, which devices support them, and how to choose the right format for your needs.
Read GuideFor readers who are curious about how CheersPDF works under the hood, here is a brief look at the key technologies involved.
When you select a file on CheersPDF, your browser reads it from your device using the JavaScript File API. This API lets web applications access files that you explicitly choose, without requiring a server. The file data stays in your browser's memory and is never transmitted anywhere. This is the same API that email clients use when you attach a file to a message — your browser reads it locally before anything else happens.
Parsing a complex ebook file can be computationally intensive. If we did that work on the main browser thread, your page would freeze until the conversion finished. Instead, we offload heavy processing to Web Workers — background threads that run in parallel without blocking the user interface. This means you can continue scrolling, clicking, or switching tabs while your file is being converted. Web Workers are the same technology that powers complex web applications like Google Sheets and Figma.
CheersPDF is built on top of well-established open-source libraries: jsPDF for PDF generation, JSZip for archive handling, and pdf.js (Mozilla's open-source PDF rendering engine) for reading PDF files. These libraries are used by thousands of projects worldwide and are continuously reviewed by the open-source community. We chose them specifically because they are battle-tested, well-documented, and actively maintained.
Modern browsers run JavaScript in a sandboxed environment that is isolated from the rest of your operating system. This means that even if a web application tried to access files outside of what you explicitly selected, the browser would block it. The sandbox is the same security boundary that protects your passwords, cookies, and banking data from malicious websites. CheersPDF runs inside this sandbox, which means your files are handled with the same level of security that protects everything else you do in your browser.