A DOCX file is a Word document saved in a modern format that Microsoft introduced in 2007

DOCX stands for "Office Open XML Document" and is the standard format Microsoft Word uses when you save a document today. It replaced the older DOC format, which was harder for other programs to read. When you open Microsoft Word and create a new document, save it, and close it, you are creating a DOCX file — the file name ends with .docx.

The key difference between DOCX and the older DOC format is that DOCX files are built on a more open standard. This means other software companies can build tools to read and edit DOCX files without needing permission from Microsoft. As a result, you can open a DOCX file in Word, Google Docs, LibreOffice, Apple Pages, and dozens of other programs.

DOCX files contain everything you put into a document: text, images, tables, formatting like bold and italics, page breaks, headers and footers, and comments. All of that information is stored in a compressed folder structure that computers can understand and move between programs.

Key Takeaways

  • DOCX is the file format Microsoft Word uses by default, and it has been the standard since 2007.
  • You can open DOCX files in Word, Google Docs, LibreOffice, Apple Pages, and many other programs on Windows, Mac, and mobile devices.
  • DOCX files preserve formatting like fonts, colors, bold text, and images when you move them between different programs.
  • If you need to send a document to someone and are not sure what program they use, DOCX is usually the safest choice because almost every device can open it.

How DOCX differs from other document formats

The format you choose affects who can open your document and whether the formatting stays the same. PDF files lock the document so no one can edit it without special tools — useful when you want to send something that cannot be changed. DOC files are the older Word format from before 2007 and work on older computers, but some newer features do not translate well. TXT files contain only plain text with no formatting at all, which is why they open on every device but look plain.

Google Docs saves files in its own format by default, but you can download your work as a DOCX file to use in Word or send to others. Apple Pages creates documents in a Pages format, but can also save as DOCX. LibreOffice, a free alternative to Microsoft Office, reads and writes DOCX files without any trouble. The reason DOCX became the standard is that it works across all these programs without losing your formatting.

Opening a DOCX file on different devices

On a Windows computer, double-clicking a DOCX file opens it in Microsoft Word if Word is installed. If you do not have Word, you can open DOCX files in Google Docs by uploading the file to your Google Drive, or use free programs like LibreOffice Writer or WPS Office. On a Mac, the same options work — Word, Google Docs, or free alternatives like LibreOffice.

On an iPhone or iPad, you can open DOCX files in the Microsoft Word app, Google Docs app, or Apple Pages. On Android phones, the Word app and Google Docs both handle DOCX files. Many email programs also let you preview a DOCX attachment without opening a separate program, though editing usually requires opening it in Word or another full editor.

What happens when you edit a DOCX file in different programs

When you open a DOCX file in Microsoft Word and make changes, Word saves those changes in the same DOCX format. If you open that same file in Google Docs, make edits, and download it as DOCX, the file stays compatible with Word. Most of the time, formatting like fonts, colors, bold text, and images transfer without problems.

Some advanced features do not always survive the trip between programs. If you use a feature that only exists in Word — like certain types of fields or macros — those may not work the same way in Google Docs or LibreOffice. For everyday documents with text, images, tables, and basic formatting, moving between programs causes almost no problems. If you are working with a complex document that uses specialized Word features, it is safer to keep it in Word.

When to use DOCX instead of other formats

Use DOCX when you are writing something that other people need to edit or when you are not sure what program the person receiving it will have. DOCX is the safest choice for sharing because almost every computer and phone can open it. If you are sending a resume, a letter, a report, or any document that might be edited by someone else, DOCX is the standard format they expect.

Use PDF instead when you want to lock the document so no one can change it — useful for contracts, official forms, or anything you want to look the same on every screen. Use TXT for simple notes or code that does not need formatting. Use your program's native format (like Google Docs format or Pages format) only when you are working alone and do not need to share the file.

File size and storage

DOCX files are compressed, which means they take up less space on your computer than older DOC files. A typical document with text and a few images might be 50 to 500 kilobytes — small enough that email services have no trouble with it. If your document contains many high-resolution images or videos, the file size grows, but DOCX compression keeps it smaller than it would be in other formats.

Because DOCX files are compressed, they are also faster to upload and download. If you are storing documents in cloud storage like OneDrive, Google Drive, or Dropbox, DOCX files use less of your storage space than uncompressed formats would.

Frequently Asked Questions

Can I open a DOCX file without Microsoft Word?

Yes. Google Docs, LibreOffice, WPS Office, Apple Pages, and many other programs open DOCX files. On phones, the Word app, Google Docs app, and Pages app all work. You do not need to own Microsoft Word to read or edit a DOCX file.

Will my formatting stay the same if I open a DOCX file in a different program?

Most of the time, yes. Text, images, tables, bold, italics, and colors transfer between Word, Google Docs, and LibreOffice without problems. Some advanced Word features may not work the same way in other programs, but everyday formatting is safe.

What is the difference between DOCX and DOC?

DOC is the older Word format from before 2007. DOCX is the newer format that other programs can read more easily. DOCX files are also smaller and more reliable. If someone sends you a DOC file, you can open it in modern Word, but DOCX is what Word creates by default now.

Can I convert a DOCX file to PDF?

Yes. In Microsoft Word, use File > Save As and choose PDF from the format list. Google Docs and LibreOffice have the same option. This locks the document so no one can edit it, which is useful for sending final versions.

Is it safe to download a DOCX file from the internet?

DOCX files themselves are not dangerous, but like any file from the internet, only download from sources you trust. Malicious code can be hidden in Word documents, so be cautious about opening DOCX files from unknown senders, especially if they ask you to enable macros.