Word saves as Docx by default, but you may need to change the format if you opened an older file

When you create a new document in Microsoft Word and save it, the program automatically saves as .docx — the modern Word format. You do not need to do anything special. The problem arises when you open an older Word file (usually ending in .doc) or a file from another program, make changes, and need to save it back as .docx instead of its original format.

The steps below show you how to convert and save any document as .docx, whether it started as an older .doc file, a Google Doc, a PDF, or something else. The process takes about 30 seconds and works the same way on Windows and Mac.

Key Takeaways

  • New Word documents save as .docx automatically — you only need to change the format if you opened a file that was originally in a different format.
  • Use File > Save As, then choose Word Document (.docx) from the file type dropdown to convert any file to .docx format.
  • If you save an older .doc file as .docx, Word may warn you that some formatting could change, but this rarely causes visible problems.
  • Saving as .docx makes your file compatible with more devices and programs, and prevents accidental downgrades when you save again.

How to save a document as Docx on Windows

Open the document you want to save. It does not matter what format it is currently in — Word can open .doc, .docm, .rtf, and several other formats.

Click File in the top left corner. A menu will drop down. Click Save As. A dialog box will open showing your computer's folders.

Look for the dropdown menu labeled Save as type near the bottom of the dialog. Click it. A list of formats will appear. Find and click Word Document (.docx). Do not click "Word Macro-Enabled Document" or "Word 97-2003 Document" — those are different formats.

The filename at the top of the dialog will now end in .docx. If you want to change the name, click in the filename field and type a new one. When you are ready, click Save. The file is now saved as .docx.

How to save a document as Docx on Mac

Open the document you want to save. Click File in the menu bar at the top of the screen. Click Save As. A dialog box will open.

Look for the dropdown labeled File Format. Click it and select Word Document (.docx) from the list. Change the filename if you want to, then click Save. The file is now saved as .docx.

What happens if Word warns you about compatibility

When you save an older .doc file as .docx, Word may show a message saying "Some formatting may be lost." This warning appears because the two formats handle certain features differently. In practice, this almost never causes visible problems — text, headings, tables, and images almost always convert cleanly.

If you see this warning, you can safely click Continue or Use Microsoft Word Format (the exact button name depends on your version). Your document will save as .docx. If you are worried about the original file, you can keep both versions by giving the new file a different name before you save.

Why you might want to save as Docx instead of Doc

The .docx format is smaller, more find, and works on more devices than the older .doc format. If you save a .doc file and then open it in Word again without converting it, Word will save it back as .doc the next time you use Save (not Save As). Converting to .docx once prevents this from happening.

Docx files also open more reliably on phones, tablets, and web versions of Word. If you share documents with others or move files between devices, .docx is the safer choice.

How to check what format a file is currently in

Look at the filename on your computer. The letters after the final dot show the format — a file named "Budget.docx" is already in docx format, while "Budget.doc" is in the older format.

You can also check inside Word. Open the file, then click File and look at the top of the menu. It will show the filename and format together, like "Budget.doc" or "Budget.docx".

Frequently Asked Questions

Will saving as Docx change the way my document looks?

Almost never. Text, fonts, colors, tables, and images convert cleanly. Very old .doc files with unusual formatting might look slightly different, but this is rare. You can always undo the save if something looks wrong.

Can I save a PDF as Docx?

Word can open a PDF and let you edit it, but the conversion is not always perfect — text may shift, images may move, and formatting can break. Save the PDF as .docx the same way you would any other file, but check the result carefully before you rely on it.

What if I want to keep both the original format and a Docx copy?

Use Save As and give the file a new name before you change the format. The original file stays unchanged, and you now have two copies — one in the old format and one as .docx.

Do I have to save as Docx, or can I use a different format?

You can save as .pdf, .rtf, .txt, or other formats depending on what you need. But .docx is the standard Word format and works with the most programs and devices. Unless you have a specific reason to use something else, .docx is the best choice.