Document and archive formats: which one to choose and what each one keeps
Choosing a document or archive format depends on what you're going to do with it: edit it, share it exactly as it looks, extract only the text, publish it as an e-book, or simply group and compress several files. This guide isn't an exhaustive list of extensions: it's a practical aid for deciding which format fits your need and understanding what information can get lost when converting from one to another.
Everything described here about what each conversion keeps or loses matches what QuickToolio's tools actually do, not what that format could abstractly do in some other program. A DOCX opened in Word supports tables, images and complex layout; a DOCX conversion done here, not always.
DOCX
- Main use
- Editable text document
- Editing
- Editable in Word or compatible word processors
- Design/structure
- QuickToolio's conversions keep headings, paragraphs, single-level lists, bold and italic; they don't keep tables, images, fonts or pagination
- Practical advantage
- Easy to keep editing afterwards
- Main limitation
- A conversion from another format doesn't reconstruct the full original design
- When to choose it
- When you need to keep modifying the content
- Main use
- Fixed-appearance document, for reading or printing
- Editing
- Not editable as text (no PDF editing tools in this guide)
- Design/structure
- Meant to keep a final presentation; converting to PDF here doesn't guarantee perfect fidelity of original tables, images or fonts
- Practical advantage
- Looks the same on any device
- Main limitation
- Extracting its content to editable text doesn't recover the original design
- When to choose it
- When you want to share or print without the look changing
TXT
- Main use
- Text with no formatting at all
- Editing
- Editable in any plain text editor
- Design/structure
- None: no headings, styles, images or tables
- Practical advantage
- The simplest and most compatible format there is
- Main limitation
- Doesn't support any kind of visual formatting
- When to choose it
- When you only care about the content, nothing else
HTML
- Main use
- Structure meant to be displayed on a website
- Editing
- Editable as code or in a visual editor
- Design/structure
- Semantic structure (headings, paragraphs, lists, links) via tags; visual appearance depends on separate CSS
- Practical advantage
- Interpreted directly by any browser
- Main limitation
- Not a format meant to be edited as an office document
- When to choose it
- When the final destination is a web page
Markdown
- Main use
- Text with lightweight syntax for basic structure
- Editing
- Editable in any text editor
- Design/structure
- Headings, lists, bold/italic and links via simple symbols; no complex tables or layout
- Practical advantage
- Lightweight, readable even unconverted, and easy to version
- Main limitation
- Doesn't reproduce complex visual design
- When to choose it
- When you want simple, portable structure (for example, a README)
EPUB
- Main use
- Digital publication meant for e-readers
- Editing
- Not meant to be edited as an office document
- Design/structure
- Reflowable text that adapts to the screen; no fixed pages like a PDF
- Practical advantage
- Adjusts to the reader's font size and screen
- Main limitation
- Not suited for keeping a fixed layout
- When to choose it
- When the document will be read in an e-reader app or device
ODT
- Main use
- Editable text document (open format)
- Editing
- Editable in LibreOffice, OpenOffice and compatible word processors
- Design/structure
- Same conservation and limits as DOCX in QuickToolio's conversions: headings, paragraphs, single-level lists and bold/italic yes; tables, images, fonts and pagination no
- Practical advantage
- Open format, not tied to one specific program
- Main limitation
- Less widespread than DOCX in environments that only expect Word
- When to choose it
- When you prefer an open office format and still need to edit
Editable document vs. final format
DOCX and ODT are editable formats: meant for continuing to work on the document with a word processor. PDF, on the other hand, is oriented toward keeping a stable final presentation, for reading or printing without the look changing across devices; it's not a format meant for editing, and converting a document to PDF here doesn't promise perfect fidelity to the original.
TXT is plain text with no formatting. Markdown is text with lightweight syntax (symbols like # or ** instead of a formatting menu) that stays readable as plain text. HTML is a structure meant for the web, interpreted by browsers. EPUB is a publication adaptable to e-readers, with text that reflows to the screen instead of fixed pages.
What "keeping the format" means
"Format" can refer to several different layers: semantic structure (headings, paragraphs, lists), style emphasis (bold, italic), visual design (colors, element positioning), pagination, images, tables, typefaces, and metadata (author, date, document properties). A conversion can keep some layers while losing others at the same time.
Extracting vs. converting
Extracting text pulls out only the raw content, as plain text, with no headings or formatting. Converting to an editable document (DOCX) keeps the basic semantic structure to the extent the target format supports it, not just loose text. Generating a PDF produces a fixed-appearance document meant for distribution or printing. Generating an EPUB produces a publication adaptable for e-readers. Converting to HTML or Markdown keeps structure (headings, lists, emphasis) without complex visual layout.
OCR is different from normal text extraction: it's used when the source is actually an image (a scanned PDF or a photographed page) with no real, selectable text layer. OCR visually recognizes characters, and the result can contain recognition errors, especially with low-quality scans or unclear typefaces; it doesn't recognize handwriting, and for now it only recognizes text in Spanish and English.
Which format to choose based on your need
- I want to edit the document: DOCX or ODT, formats meant for word processors.
- I want to share it keeping its appearance: PDF, with a fixed look on any device.
- I only need the text: extraction to TXT, with no formatting or structure.
- I want to publish it on a website: HTML, or Markdown if the destination supports it.
- I want to create an e-book: EPUB, with text that adapts to the reader's screen.
- I want to keep a simple structure: Markdown, lightweight and easy to reuse.
- I have a scanned document: you need OCR, not normal text extraction.
- I need to import content into another system: HTML or Markdown tend to be easier for other tools to interpret than a DOCX or a PDF.
Archives and containers: ZIP, RAR, 7Z, TAR, GZ, CBZ and CBR
ZIP is the most compatible format: almost any operating system opens it without installing anything, and it's the only archive format you can create from scratch in QuickToolio (besides CBZ, for comics). RAR and 7Z can be opened, extracted and converted to ZIP here, but not created as original RAR or 7Z files.
TAR isn't a compressor: it simply bundles several files into one without reducing their size; don't treat it as a direct equivalent of ZIP. GZ, by contrast, compresses a single file or stream, it doesn't bundle several files the way TAR does. TAR.GZ combines both: it bundles with TAR and compresses that bundle with GZ, and QuickToolio handles it as one combined process, not two independent steps.
Password-protected RAR files (RAR4 and RAR5) can be opened, extracted and converted to ZIP if you know the password. Password-protected 7Z files aren't supported here. There's no universal password support, and no tool to repair damaged archives.
CBZ and CBR are comic formats built on these same containers: a CBZ is, at its core, a ZIP full of images (one per page), and a CBR is the same but in RAR. They can be read directly, have their images extracted, be converted to PDF, and a CBR can be converted to CBZ. A CBZ can be created from your own images; a CBR can't be created from scratch here, just like RAR.
Quick decision for archives
- Compatibility: ZIP is the most compatible with any system; RAR and 7Z need extra software outside of here to be created.
- Grouping several files: ZIP, TAR, TAR.GZ, RAR and 7Z group several files; GZ only compresses one.
- TAR and GZ relationship: TAR groups without compressing, GZ compresses without grouping, TAR.GZ does both combined.
- Reading and extraction: ZIP, RAR, 7Z, TAR, TAR.GZ and GZ can all be opened and extracted here; so can CBZ and CBR, as comics.
- Creation available: a brand-new archive can only be created from scratch in ZIP or CBZ.
- Main limitation: RAR and 7Z can't be created here, password-protected 7Z isn't supported, and there's no tool to repair damaged archives.
What QuickToolio can actually do
Document conversion between DOCX, ODT, PDF, TXT, HTML, Markdown and EPUB (with the conservation and limits described above), plain text extraction, reading EPUB, CBZ and CBR directly in the browser, and creating, extracting and converting archives.
Convert an EPUB to Word (DOCX)
Local processing and real limits
Documents and archives are processed in your browser, so the practical limit depends on your device's memory: a very long document, an archive packed with lots of items, or very complex layout can take longer or, on devices with little memory, fail to finish. An encrypted document or a password-protected 7Z can't be processed here; a password-protected RAR can, if you know the password. A damaged or incomplete file may fail to open, with no guaranteed recovery. OCR recognizes sharp, high-contrast pages best, and can fail with low-quality scans.
Changing a file's extension (for example, renaming a .txt to .docx) doesn't change its actual content: the format depends on how the information is encoded inside, not on the file's name.
Frequently asked questions
Which format best preserves the design?
It depends on the source: if the document is already a PDF with a good design, that design stays intact when reading it. But a conversion to PDF done here from DOCX, ODT or another format doesn't guarantee recovering the original tables, images or fonts.
Does converting PDF to DOCX recover the original document?
No. A PDF doesn't have a reliably recoverable editable structure, so this conversion only reconstructs the textual content as editable paragraphs, without the original design, tables or images.
Does TXT keep images or styles?
No. TXT is plain text: it doesn't support any kind of visual formatting, style or image.
Are Markdown and HTML the same thing?
No. Markdown is a lightweight plain-text syntax meant to be written by hand easily; HTML is a more complete markup language, meant to be interpreted by a browser.
Does EPUB keep fixed pages?
No. An EPUB's text reflows to the reader's screen size and font, so it doesn't have fixed pages like a PDF.
Are ZIP, RAR and 7Z equivalent?
No. They share the idea of grouping and compressing files, but differ in compatibility and in what can be done with them here: only ZIP can be created from scratch; RAR and 7Z can only be opened, extracted or converted to ZIP.
Why do TAR and GZ appear together?
Because TAR.GZ combines both: TAR groups several files into one without compressing, and GZ compresses that result. Separately, TAR only groups and GZ only compresses a single file.