DOC vs DOCX: Key Differences, Compatibility & Which Format to Use
DOC is the legacy binary file format used by Microsoft Word 97-2003; DOCX is its XML-based successor introduced in Word 2007, smaller and more robust.
People still see “.doc” attached to old resumes or legal docs emailed years ago, so they panic when newer PCs flag the file. That nostalgia keeps the confusion alive.
Key Differences
DOC stores data in a single binary stream—bulky, corruption-prone. DOCX splits content into zipped XML parts, cutting file size ~75 % and enabling faster repairs plus richer metadata.
Which One Should You Choose?
Use DOCX for everything new; it’s supported by Google Docs, LibreOffice, and Microsoft 365. Reserve DOC only if a vintage system or court filing explicitly demands the old format.
Can I convert DOCX back to DOC?
Yes—Word’s “Save As” or cloud converters handle it, but advanced formatting may flatten.
Is DOCX safer from viruses?
Generally yes; its open structure lets antivirus scanners inspect XML parts more easily than opaque DOC binaries.
Will DOC ever disappear?
Unlikely soon; legacy enterprise and legal archives keep it alive, though new features won’t backport.