OmniDocWhat file is docx and what is the difference between it and doc
Explain clearly what format docx is, the differences in storage methods, compatibility and macro support between it and the old version of doc, and provide methods to determine which format to use and how to confirm the file type.
Key points of this article
- Docx is a compressed package format based on XML, and doc is an early binary format. The internal structures of the two are different, and they cannot be interchanged just by changing the suffix name.
- docx has become the default format since Word 2007. Most office software can now read and write it, making it suitable for daily saving and sharing.
- When you need to save macros, docx will not work. You should use docm format with macros instead. Do not mix the two.
- You can check the file type by looking at the suffix, or you can open docx as a compressed package to view the internal files. Changing the suffix cannot convert the format.
When many people download attachments, save documents or send them to others, they will see the two suffixes "docx" and "doc", but they don't know whether they are the same thing. Some people think that docx is the "new version of the document", while others think that docx is an electronic document format with a similar name to doc. Once you understand this, you will know how to deal with the situation when it cannot be opened, the layout is messed up, or someone urges you to change the format.
This article is written for people who often send and receive Word files and want to figure out the relationship between the two formats. After reading, you can answer whether docx is an electronic document, know the structural difference between it and doc, and judge which format should be saved according to the actual situation, and you can also confirm for yourself what type of file a file is.
Do you want to save the file as docx? One sentence conclusion
docx is an electronic document format, and you can safely use it to save daily text documents; only when the other party or a certain system explicitly requires the old format, you need to keep doc.
| your situation | Recommended practices | reason |
|---|---|---|
| Daily writing, report writing, contract draft writing | Save as docx | Most office software supports it by default, is usually smaller in size and has good compatibility. |
| The other party explicitly requires submission of doc | Save as doc as requested by the other party | The other party's review or filing system may only recognize the old format. |
| Document contains macros (automation scripts) | Save as docm, not docx | Macros cannot be saved in docx, and the macros will be lost after saving. |
| Received an old file with the suffix doc | First save as docx and then edit | The new format has more complete editing functions and is more convenient for subsequent sharing. |
| Requires long-term archiving | Also keep the original file and consider converting it to PDF | Format and fonts depend on the software environment, and PDF is more convenient for fixed layout |
What is the relationship between docx and doc?
Both docx and doc are document formats used by Word, but their internal structures are completely different. This is the key to understanding the difference between the two.
docx: The compressed package contains a set of XML files
docx belongs to the Office Open XML format and is the default format adopted by Word 2007. Its essence is a compressed package, which contains several XML files, respectively recording text content, paragraph styles, table structure, page settings and other information. Pictures and other materials are stored separately in the media directory in the compressed package.
This structure brings several practical benefits: the content is organized in text form, making it easier for other programs to read and process it; compressed storage generally makes files smaller; and when exchanging data between different software, compatibility is easier to achieve than with older formats.
doc: early binary format
doc, the format used by earlier versions of Word, is stored internally in binary and can only be read by programs that can parse it correctly. It was the universal standard for quite some time and therefore still exists in large numbers in old documents, archives and historical sources.
The problem with the binary format is that the structure is opaque and there are many compatibility details between different versions. It is also troublesome for other software to fully support it.
Common misunderstanding: Just change the suffix
Many people will directly change the suffix of the doc file to docx. As a result, the file may not be opened, or the format may be disordered after opening. The reason is simple: the suffix name only tells the system what program to use to open the file, and does not change the internal structure of the file. The internal formats of the two are different. If you just change the suffix name without conversion, the program will parse it according to the wrong structure.
The correct way is to open the old file with office software, and then select docx format to save it through "Save As". In this way, the software will rewrite the content according to the rules before the conversion is truly completed.
Another source of confusion is docx and docm. docm is also an XML-based format, but it allows saving macros, which docx does not. If there are macros in your document, save it directly as docx and the macros will be deleted.
📊 Core comparison
| Comparative item | doc | docx |
|---|---|---|
| Internal structure | Binary format, structure not opaque | The compressed package contains XML files with a clear structure |
| Appearance time | A commonly used format in early versions of Word | Word has been the default format since 2007 |
| Is it possible to directly change the suffix and swap it? | No, you need to save as a conversion | No, you still need to save as a conversion |
| Whether to preserve macros | Yes, you can | No, macros should use docm |
| Legacy software opening | Older software can be opened directly | Older versions may require installing compatibility packages to open them |
| Other programs are difficult to read | Relatively high | Lower, and the content is organized in text form |
How to actually use it
If you need to process Word documents on OmniDoc, you can follow the steps below.
- Confirm file type: Check the file extension. If it's .docx, treat it as docx; If it's .doc, save it as docx in office software first, then continue using it.
- When translation is needed: Upload the docx file in omnidoc.top, choose bilingual or just translation, and wait for processing to finish downloading the result. Layouts, tables, and images are retained as factual, but important content still requires manual verification.
- When you need to edit online: You can open app.unidoc.top, a UniDoc web editor that supports Word-compatible editing and back-and-forth conversion between Word and LaTeX.
- When you need to return from PDF to Word: Open the PDF in the OmniDoc desktop client, use the export function in the PDF editor, select export as Word, and then check whether the paragraphs and tables match the original text.
If you want to install the client on your desktop, you can download it from download.omnidoc.top, which supports Windows, macOS, and Linux.
🎯 Which method suits you?
If you only write and share daily, you can just use docx directly; there's no need to worry about doc. If you need to collaborate with someone using older software, or if they explicitly require an old format, keep a copy of the doc to reduce the risk of it not being opened. If the file contains macros, select docm. The judgment is simple: first check what the other party and the system need, then decide which format to save.
❓ Frequently Asked Questions (FAQ)
1. Can docx be used directly as a doc?
Most new office software versions can open docx, but whether you can use it smoothly depends on the software version and feature support. If the other party is using very old software, you may need to install compatible components or ask them to switch to a doc format.
2. Can changing the docx extension to zip extract it?
Yes, you can. docx itself is a compressed package. Change the extension to zip and extract it to see the XML files and images inside. This method is suitable for checking file structure or troubleshooting, but don't use it to "change formatting"—the modified file may not open properly.
3. Docx files won't open—could there be a problem with the format?
Not necessarily. Files may be corrupted, incomplete, or password-protected. You can first confirm that the file size is normal, then try opening it on another device or software. If the content is important, you can back up the original file first and then proceed with the investigation.
4. What should you pay attention to when processing Docx with machine translation?
Machine translation results require manual verification, especially for technical terms, numbers, dates, and personal names. Retention of formatting does not guarantee the accuracy of the translation. Please check key content paragraph by paragraph before official release.
📝 Summary
docx is an XML-based compressed file format, currently the default format for Word, and a good choice for daily document saving. doc is an early binary format and still has its use cases, but the two cannot be swapped simply by changing the extension. When encountering formatting issues, first confirm the other party's requirements, then decide whether to save as docx, keep doc, or switch to docm.
