Why you need to save as .docx instead of other formats
When you open and edit a document in Microsoft Word, the file format it uses matters for who can read it later and whether all your formatting stays intact. .docx is Word's standard format — it preserves fonts, colors, tables, and images the way you created them, and nearly every computer can open it. Other formats like .doc (older Word), .rtf (rich text), or .txt (plain text) either lose formatting or work only on certain devices.
If you've been working in a different format and want to switch to .docx, or if you're not sure what format your document is currently in, the save-as process takes about 30 seconds and works the same way whether you're on Windows or Mac.
Key Takeaways
- Open the File menu, select Save As, and choose .docx from the file type dropdown to convert any document to Word's standard format.
- If you've never saved the document before, use Save (not Save As) and Word will default to .docx on most recent versions.
- The .docx format preserves all formatting, images, and tables, while older formats like .doc or .txt may strip out styling or special characters.
- After you save as .docx, the filename in your title bar will show the new format, and the original file in the old format remains unchanged unless you delete it yourself.
How to save an existing document as .docx on Windows
Open the document you want to convert. At the top left, click File, then click Save As from the menu that appears. A dialog box will open showing your computer's folders and a field at the bottom labeled "Save as type" or "File name".
Click the dropdown next to "Save as type" — it probably shows something like "Word Document (.doc)" or "Rich Text Format (.rtf)". From the list, select Word Document (.docx). The filename field above it will stay the same unless you want to rename the file. Click Save at the bottom right. Word will convert and save the file in .docx format in the same folder where the original was stored.
How to save an existing document as .docx on Mac
Open the document. Click File in the menu bar at the top, then click Save As. A sheet will slide down from the top of the window with a filename field and a dropdown labeled "File Format".
Click the "File Format" dropdown and select Word Document (.docx). The filename stays the same unless you change it. Choose the folder where you want to save it — the default is usually Documents. Click Save. Mac will convert and save the file in .docx format.
What happens to the original file after you save as .docx
When you use Save As, Word creates a new file in .docx format and closes the old one. The original file — whether it was .doc, .rtf, or another format — stays on your computer in its original format unless you delete it yourself. You now have two separate files: the old one and the new .docx version.
If you want to keep only the .docx version, you can delete the original file by opening your file explorer (Windows) or Finder (Mac), finding the old file, and moving it to the trash. This step is optional — keeping both files takes up minimal space and gives you a backup if something goes wrong.
How to check what format a document is currently in
Look at the filename in the title bar at the very top of the Word window. If it ends in .docx, the file is already in the format you need. If it ends in .doc, .rtf, .txt, or another extension, you should save it as .docx using the steps above.
You can also right-click the file in your file explorer or Finder, select Properties (Windows) or Get Info (Mac), and look for "File type" or "Kind" — it will show you the current format. This is useful if you're not sure which files in a folder need converting.
Why Word sometimes defaults to .docx automatically
If you create a brand-new document in Word and use Save (not Save As) for the first time, Word on recent versions — 2016 and newer on Windows, 2016 and newer on Mac — will save it as .docx by default. You don't need to do anything special. Older versions of Word defaulted to .doc, which is why you might see that format in documents created years ago.
The only time you need to manually choose .docx is when you're converting an existing file from a different format, or when you want to change the format of a document that's already saved.
Frequently Asked Questions
Will saving as .docx change the way my document looks?
No. The .docx format preserves all formatting, fonts, colors, images, and tables exactly as they appear. If anything looks different after saving, it's usually because the original file was in a format that didn't support certain features, and those features are now visible in .docx.
Can I open a .docx file on a Mac or older computer?
.docx files open on Mac, Windows, and most tablets and phones. Older computers running Word 2003 or earlier need a free converter from Microsoft, but this is rare. Google Docs, LibreOffice, and most other word processors also open .docx files without any problem.
What if I accidentally saved over my original file?
If you used Save As and chose the same filename, Word will ask you to confirm before overwriting. If you already confirmed, the original file is replaced. You can undo this by pressing Ctrl+Z (Windows) or Command+Z (Mac) when ready, as long as you haven't closed the document yet.
Do I need to save as .docx every time I edit the document?
No. Once you've saved a document as .docx, every time you press Ctrl+S (Windows) or Command+S (Mac) to save, it stays in .docx format. You only need to use Save As if you want to change the format again or save it with a different name.