OmniDocWhat is the difference between EPUB and PDF: How to choose the format before translation
Compare the differences in reading and translation between EPUB, PDF and plain text formats, explain which format retains the format and which format reflows with the screen, and provide a method to determine which format to choose based on the purpose.
Key points of this article
- PDF fixed page layout is suitable for files that retain layout, tables and formulas. Whatever the original text looks like, the translation will roughly look like.
- EPUB is a reflowable e-book format. The text will wrap according to the screen size, making it suitable for continuous reading in a reader.
- Plain text only has words and no layout. It usually needs to be sorted into Word or Markdown before being processed.
- The scanned PDF itself is a picture, and you can directly upload the translation, but you must first determine whether it is a scan.
- When choosing a format, ask two things first: whether you want to keep the layout, and what device you will use to read it on.
If you have an English e-book, a paper or a document and want to translate it into Chinese, you will often encounter a question: Should this file be saved as EPUB or PDF? Both formats look like a book on the screen, but the underlying logic is completely different. If you choose the wrong one, subsequent reading and proofreading will be more troublesome. Some people only have TXT plain text in their hands and are not sure whether they can be translated directly.
This article is written for readers who are preparing to translate books, papers or materials. It does not talk about the structure of the EPUB format itself, but only compares the differences in reading and translation between EPUB, PDF and plain text, explaining which one retains the layout, which one will be rearranged with the screen, and what to pay attention to when translating each type of file on OmniDoc. After reading it, you will be able to directly determine which format to use according to the purpose.
Which one is better, EPUB or PDF? One sentence conclusion
There is no absolutely better format. If you want to retain the layout, tables, formulas, and pictures of the original book, PDF is more stable; if you want to read the text continuously on your mobile phone or e-reader, EPUB is more suitable.
| your situation | Recommended practices | reason |
|---|---|---|
| Papers and reports, including formulas, tables and charts | Use PDF, choose bilingual comparison or translation only when translating | PDF fixed pages, layout, tables, formulas and pictures should be retained as much as possible after translation |
| Novels or non-technical books, mainly read on mobile phones | Use EPUB | The text will wrap according to the screen size, and the font size and page turning method can be adjusted. |
| Scanned paper books or old materials | Upload scanned PDF directly | Scanned documents are essentially pictures and can be processed on a page-by-page basis. OmniDoc supports scanned PDF translation. |
| Text-only notes or drafts | Organize into Word or Markdown first, then upload | TXT is not in the list of translatable formats. It is safer to switch to a structured format. |
| Not sure if typesetting needs to be preserved | First upload a short trial translation using PDF | Check whether the paragraphs, titles and figure positions of the translated text are as expected |
The fundamental difference between the two: fixed page or reformatting
PDF records where every word, line, and picture is placed on each page. It's like taking a photo of the paper and then digitizing it. The page size, margins and columns are all fixed. Therefore, it is suitable for scenarios where it is necessary to "match the page number", such as citing the page number of a paper, or proofreading against the paper version.
EPUB does not record pages. It saves chapters, paragraphs and text content, which are re-formatted by the reader according to the screen width and font size when reading. The same EPUB will have different line breaks when viewed on a mobile phone and a computer, but the chapter structure will not be messed up.
How it works: What happens to the layout after translation
When translating on OmniDoc, the results depend on the output method you choose. If you choose bilingual comparison, the translation and original text will appear together, suitable for paragraph-by-paragraph verification; if you choose translation only, you will get a file containing only Chinese, suitable for direct reading or printing. PDF usually retains the layout of the original page, and the positions of tables, formulas, and pictures are also maintained as much as possible; EPUB retains the chapter and paragraph structure, and can still be rearranged with the screen when reading.
One thing to note: the length of Chinese translations is usually different from English translations, and individual long paragraphs may need to be line-wrapped. This is normal and does not mean the format is lost.
Common misunderstanding: Scanned PDF and text PDF are not the same thing
Many people think that all PDFs can copy text directly, but this is not the case. The judgment method is simple: open the PDF and try to select a piece of text with the mouse. If it can be selected and copied, it means it is a text version; if it cannot be selected, it is mostly a scanned copy, and each page is actually a picture.
Scanned documents can also be uploaded for translation directly without any additional processing. If you still want to modify the text locally, you can use OCR recognition in the PDF editor on the desktop client before editing.
Another common misconception is that EPUB is necessarily smaller and more suitable for translation than PDF. Both the file size and the translation effect depend on the original content: for a book with mainly pictures, the EPUB may be very large; for a text-only report, the PDF may also be very light. Don’t judge based on format alone.
📊 Core comparison
| Comparative item | EPUB | Plain text (TXT) | |
|---|---|---|---|
| Layout | Rearrange with the screen | Fixed page | No layout, only text. |
| Formulas, tables, pictures | Depending on the original document, it is suitable for text-based content | Can be retained and fixed in position | It is almost impossible to express. |
| Page number correspondence | There is usually no fixed page number. | The page number is fixed | No page number |
| Translate on OmniDoc | Support | Yes, both digital version and scanned version | Not in the support list. You need to change to Word or Markdown first. |
| Suitable for the scene | Continuous reading by mobile phone and e-reader | Papers, reports, materials that need to be compared to the page | Drafts and notes should be sorted out before use |
# how to use it
- Confirm the file type first. If it is EPUB, upload it directly in omnidoc.top; if it is PDF, select a piece of text with the mouse to determine whether it is a text version or a scanned piece.
two. Determine whether layout is required according to the purpose. You need to compare page numbers, retention formulas and tables. Choose PDF; just to read it comfortably. Choose EPUB.
- If you have TXT in your hand, first sort out the paragraphs and headings in the word processor, save them as Word or Markdown, and then upload them to avoid the loss of all structural information.
- After uploading, choose the output mode: to compare paragraph by paragraph, choose bilingual control; as long as the translation, choose only the translation.
- After downloading the translation, spot check several important paragraphs, especially terms, numbers and formulas. There will inevitably be errors in machine translation. Please check the important contents with the original text.
# which method is suitable for you?
-to do academic research, you need to quote the page number: give priority to PDF, choose bilingual control, and facilitate paragraph-by-paragraph check. -Reading foreign novels on mobile phones: give priority to EPUB, only choose the translation when you need it, it is easier to read. Only plain text drafts are available: first organize them into Word documents with paragraphs and headings, then translate them. Scanned old books or photocopies: upload scanned PDF directly without having to convert the format first.
# frequently asked questions (FAQ)
1. What's the difference between EPUB and TXT?
TXT has only plain text and no chapter, catalog and style information. EPUB is a structured e-book format with chapter division and typesetting information in the file, from which the reader can generate a directory and adjust the layout.
2. Which is better, epub or pdf?
Depends on the purpose. Read and adjust the font size continuously. To select EPUB;, you need to keep the page number, formula and table as is, and choose PDF.
3. Can the scanned PDF be translated directly?
Sure. OmniDoc supports scanned PDF translation. After uploading, you can directly select the output method. If you want to edit the text locally, you can use OCR to identify it in the PDF editor on the desktop client and then modify it.
# Summary
The choice of format starts with two things: whether you want to keep the layout of the page and what device to read it on. PDF needs to be compared with page numbers and typesetting papers and reports, EPUB is selected for e-books that read continuously, and plain text is sorted into structured documents before translation. After the translation is finished, don't forget to spot-check terms, numbers and formulas.
