DOC vs DOCX: What's the Difference?
Both are Microsoft Word documents. .doc is the older format, used
until 2007; .docx is the modern one. Unless you have a specific reason, save in
.docx.
What is a .doc file?
.doc was Word's main format for many years, and the version you'll meet today
is the one used by Word 97 to Word 2003. It's a "binary" format: the document is stored in a
structure that only programs that understand it can read. It still opens in every modern
version of Word, and in Google Docs and LibreOffice.
What is a .docx file?
.docx arrived with Word 2007 and has been the default ever since. Inside, a
.docx is a compressed folder (a ZIP file) of text files in a format called XML,
following an open standard known as Office Open XML. You can see this for yourself: copy a
.docx, rename the copy to end in .zip, and open it.
Why .docx is better
- Smaller files. The contents are compressed, so documents, especially ones with pictures, usually take up less space.
- Easier to recover. Because the parts are stored separately, a damaged file is often partly recoverable.
- Safer. Ordinary
.docxfiles can't contain macros (small programs). Documents with macros must be saved as.docm, so you can tell them apart. - Works everywhere. As an open standard,
.docxis read well by Google Docs, Apple Pages, LibreOffice and many phone apps. - All of Word's features. Some newer Word features aren't available in
.doc, and Word opens such files in "Compatibility Mode".
When might you still need .doc?
Rarely. Occasionally an old piece of business software, or someone using Word 2003 or
earlier, needs .doc. If so, save a copy with File → Save As and
choose Word 97-2003 Document (*.doc).
How to change .doc to .docx
- Open the
.docfile in Word. You'll see "Compatibility Mode" next to the name. - Go to File → Info → Convert (on Windows), or File → Save As and choose Word Document (.docx).
- Check the layout. Occasionally spacing shifts slightly when an old document is upgraded.
Turning either into a PDF
SwapDoc's Word to PDF converter accepts both .doc and
.docx. When converting a PDF back to Word, you'll get a .docx.