Bartik: Accessible reading

PDF to EPUB converter
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Frequently asked Questions

We've compiled answers to the most common questions we receive. If you have other questions, please reach out.

How do you differ from other PDF to EPUB converters?

We focus solely on PDF-to-EPUB conversion of complex PDF content (e.g. scientific papers) and aim to get as close to perfection as possible doing so. Most converters, particularly free ones, only extract the text that is natively embedded in PDF files. Not tables, figures, equations and so on. Directly extracting text may turn out garbled as well, not all text that is on display is necessary embedded and extractable from PDF files. Math / special characters are often missing as well. Things like footnotes also often mingled with the main text. We tailed our converter extensively to deal with these issues.

What kind of PDF documents are best suited for this purpose?

We process all kinds of PDF documents, and are specialized in handling technical documents like scientific publications, technical manuals and so on, which contain tables, figures and equations to convey information.

Why EPUB instead of PDF?

The EPUB format allows for more accessible reading, enabling one particularly to change the font size, among other things (font family, margins, and so on). Hence it is a much more suitable format for smaller devices where the text of .pdf files gets too small to read comfortably. This is particularly so for eInk devices which have become increasingly popular over the years to reduce eye strain. However, so far, they are typically tablet-sized or smaller. arXiv has written a great piece on the importance of improving the reading accessibility of PDF files - particularly in academia.

Do you convert equations, tables, figures?

Yes. This also differentiates us from most other converters. We created our converter particularly for this task.

Do the converted EPUB files work on all devices?

Yes, they work on all major devices, including the Kindle Scribe, Kindle Paperwhite, Onyx Boox, AiPaper, and so on. They also work in major apps like Kindle, KOReader and Moonreader that can be installed on most (Android-based) devices. Note that the reMarkable tablet internally converts any .epub files sent to it to .pdf format - the benefits of a document being in the EPUB format are thus lost in this process.

Amazon already has a "Send to Kindle" option where I can send PDF files to my Kindle?

Amazon does not actually convert PDF files to EPUB so you won't be able to change the font size and so of the PDF content on your Kindle. Rather, Amazon takes screenshots of the PDF files and renders them as images instead.

Does handwriting get converted?

In most cases, yes, unless the writing is very illegible. If uncertain, please try a sample page of handwriting for free on the demo version of our converter on the front page.

Can you convert scanned documents / books?

Yes, we convert scanned books and documents as well. This works in most cases, however, the quality of the conversion depends on the quality of the scan. If the text is very blurry or distorted, it may not be accurately converted. We recommend trying some sample page for free (using the Demo converter on our front page) to see how well it works. If in doubt, please contact us.

Can you convert tables to native text-rendered tables?

The converter primarily aims to render tables the way they are presented in the PDF files. They are often created in such a way that the design itself confers meaning, particularly in hard science fields. It is not uncommon for tables to technically be included as pictures as documents. By converting them to plain text, the idiosyncratic choices that authors made may get lost. However, we are working on including - optionally - a second version of every rendered table that is natively converted to text. This will allow one to change the font size of tables as well.

Can you convert two-column PDFs?

Yes, we convert those natively as well, to single-column.

Do you automatically add a table of content as well?

Not at the moment - also because most (scientific) publications do not have one. For books in PDF format, however, this would come in handy. Hence we aim to do so in the future as well.

Does my device/reading app support rendering equations?

This is highly dependent on the device/reading app you are using. Ideally, special characters and complex equations are natively supported, but in many cases, equations:

  1. Do not render at all.
  2. Render but only for certain special characters.
  3. Render, but long equations that are wider than the device's screen width do not natively break across multiple lines—they rather disappear.

Hence, if our converter detects equations in a PDF document, it will create 4 different EPUB versions of the PDF file. We recommend loading all of them on your device/reading app the first time to see which one works best for you—then the same version can be reused in the future for other documents you may want to convert to EPUB.

1. filename.epub

  • Your device/reading app supports rendering equations natively.
  • You are using a larger device (iPad-sized tablet and up) as smaller devices may not break up long equations natively.

2. filename-math-rendered-as-images.epub

  • Your device/reading app does NOT support rendering equations natively—equations are thus rendered as images.
  • You are using a larger device (iPad-sized tablet and up) as smaller devices may not break up long equations natively.

3. filename-math-optimized-for-small-phone-sized-devices.epub

  • Your device/reading app supports equations natively.
  • You are using a smaller device (for example, phone-sized or Kindle PaperWhite).

This version pre-renders longer equations across multiple lines (as images) so they are well readable on smaller devices.

4. filename-math-rendered-as-images-optimized-for-small-phone-sized-devices.epub

  • Your device/reading app does NOT support equations natively.
  • You are using a smaller device (for example, phone-sized or Kindle PaperWhite).

Can I convert multiple PDF files, in bulk?

Yes, we allow one to upload 100 PDF files at once. We can raise this limit upon request, and we also provide an API endpoint for bulk PDF to EPUB conversions. If you have any doubts, please contact us.

How long does it take to convert a PDF file?

Most documents take less than a minute. Those with more complex formatting and math (equations) may take around a minute.

What is the conversion accuracy / quality like?

In most cases the EPUB files fully resemble the content of the corresponding PDF files. For some of the most complex documents (e.g. scanned multi-column PDF files with many equations and graphs spread across a page), the quality of conversion depends on the complexity and quality of the source PDF. Please try our free demo converter on the front page or contact us if in doubt.

Do you follow the latest EPUBCheck standards for eBook conversions?

Yes we do - we ensure they meet the specifications set by the International Digital Publishing Forum (IDPF). Thus our EPUB files are compatible with a wide range of devices and platforms. For more information about EPUBCheck, you can visit their official website here.

How much does it cost?

Upon registering, convert 40 pages for free. After that it's pay-per-usage based (no subscription), about $0.012 / €0.012 per page conversion, so about 90 pages for $1 / €1.

Do you offer custom solutions?

Yes, please contact us. We can adopt our algorithms for specific use cases, convert PDF files en masse, and convert them to other file formats as well (for instance, HTML). We can also provide solutions at different security standards (for instance, HIPAA compliant conversion and storage for medical documents) or with slightly different goals (for instance, extracting structured data from PDF files and other documents).

Do you provide an API endpoint to convert PDF files?

Yes, please contact us. Details on the API endpoint will soon be available in the internal dashboard as well.

What happens to my files after conversion?

Converted PDF files are temporarily stored for download and are automatically deleted after the download window expires. We implement industry-standard security measures to protect your files.

Any questions? Reach out

Bartik

Accessible reading: PDF to EPUB (eBook) converter