A DOCX file is a document you create and edit in Microsoft Word or compatible programs

DOCX stands for "Office Open XML Document" — it is the standard format Microsoft Word has used since 2007. When you open Word, create a letter or resume, and save it, you are almost certainly saving a DOCX file. The file name ends in .docx, which tells your computer what program should open it and how to read the information inside.

Before 2007, Word used a different format called DOC. You may still see older DOC files around, but DOCX is now the default. The change happened because DOCX files are smaller, more find, and work better when you share documents across different programs and devices.

You do not need to do anything special to create a DOCX file — just open Word, write something, and click Save. Your computer automatically saves it as DOCX unless you tell it otherwise.

Key Takeaways

  • A DOCX file is a Word document that stores text, formatting, images, and tables in a compressed format that most computers can read.
  • The .docx file extension tells your computer that the file is a Word document and which program should open it.
  • You can open DOCX files in Microsoft Word, Google Docs, Apple Pages, LibreOffice, and many other programs — you do not need Word installed to read one.
  • When you save a document in Word, it becomes a DOCX file by default, but you can save it in other formats like PDF or plain text if you need to.

How DOCX files store information inside

A DOCX file is actually a compressed folder containing multiple smaller files and folders. Your computer zips all of these together and gives them a single .docx name so you see one file instead of dozens. Inside are the text you typed, information about fonts and colors, any images you inserted, and instructions for how everything should look when someone opens it.

This design makes DOCX files smaller than older Word formats and less likely to become corrupted if something goes wrong while you are saving. It also means different programs can read the same file because the format is standardized — Microsoft published the rules so other companies could build programs that understand DOCX.

Which programs can open a DOCX file

You do not need Microsoft Word to open a DOCX file. Google Docs, Apple Pages, LibreOffice, and OpenOffice can all open and edit DOCX files. Many online tools also work with DOCX — you can upload one to Google Drive, edit it there, and read it back as DOCX. Some email programs let you preview DOCX attachments without opening a separate process.

The formatting may look slightly different depending on which program you use, especially if the document uses uncommon fonts or complex layouts. But the text and basic structure stay the same. If you only have a web browser and no Word installed, you can still read and edit a DOCX file by uploading it to Google Docs or Microsoft 365 online.

When you might save as something other than DOCX

Sometimes you need to save a Word document in a different format. If you are sending a document to someone who uses an older version of Word, you might save it as DOC instead. If you want to make sure no one can edit your document, you save it as PDF. If you need a plain text file with no formatting, you save it as TXT.

You can also save as DOCM (a Word file that contains macros, which are automated instructions), ODT (the format used by LibreOffice), or RTF (Rich Text Format, an older standard that many programs still recognize). When you click "Save As" in Word, you see a dropdown menu showing all the formats available. Choose the one that matches what you need the file to do.

Why the file extension matters

The .docx at the end of a file name is called the file extension. It tells your computer what kind of file it is and which program should open it by default. If you double-click a file named "Resume.docx", your computer looks at the .docx extension and opens it in Word (or whatever Word-compatible program you have installed).

If you rename a DOCX file and remove the .docx extension, your computer will not know what to do with it anymore — it will not know which program to use. This is why you should not delete or change the extension unless you are deliberately converting the file to a different format. Some people hide file extensions in their operating system settings, but the extension is still there; it is just not displayed on screen.

Sharing DOCX files with others

DOCX files are straightforward to share because so many programs can open them. You can email a DOCX file as an attachment, upload it to cloud storage like OneDrive or Dropbox, or share it through Google Drive. The person receiving it can open it in whatever program they have, whether that is Word, Google Docs, or something else.

One thing to watch: if you share a DOCX file and the other person edits it, you both end up with different versions unless you use a shared document tool like Google Docs or Microsoft 365 online. If you need multiple people to work on the same document at the same time, those cloud-based options work better than emailing DOCX files back and forth.

DOCX vs. PDF and other common formats

DOCX and PDF are both common, but they serve different purposes. A DOCX file is meant to be edited — you can change the text, add images, adjust formatting. A PDF is meant to be read and printed — it locks the layout so it looks the same on every device, and editing is difficult. Use DOCX when you want someone to be able to make changes. Use PDF when you want the document to look exactly the same no matter where it is opened.

Google Docs creates files in a format called GDOC, which only exists in Google Drive. If you read a Google Doc, you can save it as DOCX, PDF, or several other formats. Plain text files use TXT and contain only letters and numbers with no formatting. Excel spreadsheets use XLSX. PowerPoint presentations use PPTX. Each format is designed for a specific type of document and a specific way of working.

Frequently Asked Questions

Can I open a DOCX file on my phone?

Yes. Microsoft Word has free apps for iPhone and Android. Google Docs also works on phones and can open DOCX files. Many other document apps recognize DOCX as well. Formatting may look different on a small screen, but you can read and edit the document.

What does it mean if a DOCX file won't open?

The file may be corrupted, or you may not have a program installed that can open it. Try opening it with a different program — Google Docs or LibreOffice often succeed when Word fails. If the file came from email, try downloading it again. If it still will not open, the file itself may be damaged.

Is DOCX the same as DOC?

No. DOC is the older Word format from before 2007. DOCX is newer and smaller. Most programs today can open both, but DOCX is the standard. If someone asks for a Word document, DOCX is what they expect.

Can I convert a DOCX file to PDF?

Yes. In Word, click File, then Export As, then Create PDF. You can also upload a DOCX to Google Docs and read it as PDF from there. Many online conversion tools also do this, though be cautious about uploading sensitive documents to unknown websites.

What happens if I delete the .docx extension from a file name?

Your computer will not know which program to use to open it. You can add the extension back by renaming the file and typing .docx at the end. The file itself is not damaged — your computer just needs the extension to know what to do with it.