FixFile
File Format

DOC (.doc)

Microsoft Word's legacy binary document format used from 1983 to 2007. Still widely circulated in older archives and legal documents before the DOCX transition.

Extension
.doc
MIME Type
application/msword

Last updated

Overview

DOC is the binary file format used by Microsoft Word from 1983 through Word 2003. It uses a proprietary binary structure based on the Compound File Binary Format (OLE2), storing document text, formatting, images, embedded objects, macros, and revision history in a complex binary layout. Word 2007 replaced DOC with DOCX (an XML-based format), though Word can open and save DOC files to this day.

DOC files are still encountered frequently in legal, government, and corporate archives. Many organisations retain documents in DOC format from pre-2007 systems. Academic journals and older submission systems sometimes still request DOC files.

Common Uses

  • Legacy document archives — contracts, memos, and reports created before 2007
  • Cross-version compatibility — opening DOC files in older versions of Word that predate DOCX support
  • Legal document exchange — some legal and government systems still specify DOC format for submissions
  • Template distribution — older form templates and document starters

Advantages

  • Universal Word compatibility — every version of Microsoft Word from Word 97 onward opens DOC files without conversion
  • Embeds everything — fonts, images, OLE objects, and macros are stored self-contained within the file
  • Widely understood — DOC is the assumed format for "Word document" in informal communication

Limitations

  • Proprietary binary format — structure is complex and not fully documented; non-Microsoft implementations may have minor rendering differences
  • Macro security risks — DOC files can contain VBA macros that execute automatically, making them a common vector for malware
  • Larger than DOCX — binary format is less efficient than DOCX's compressed XML; a DOC file is typically 20–40% larger
  • Outdated — DOCX is the current standard; DOC is a legacy format with no new feature development

Supported Software

  • Windows: Microsoft Word (all versions), WordPad (basic), LibreOffice Writer, WPS Office
  • macOS: Microsoft Word for Mac, Pages (import), LibreOffice Writer
  • Online: Google Docs (upload and convert), Microsoft 365 (web)