Why can't this be converted directly in the browser like your other tools?

The .doc binary format (Compound File Binary Format) packs a document into internal binary streams with hundreds of undocumented record types built up over three Word versions. No lightweight JavaScript library exists that decodes this reliably — it genuinely requires the same compatibility engine built into Word or LibreOffice, which is far too heavy to ship in a browser page.

What is the fastest completely free way to convert .doc to .docx?

If you already have Microsoft Word installed, File → Save As → choose Word Document (.docx) takes about five seconds and gives the most faithful result. If you don't own Word, LibreOffice Writer (free, open-source, no account) or uploading to Google Docs (free, browser-only, no install) both do the same job in well under a minute.

Will I lose any content converting an old .doc file?

In the overwhelming majority of cases, no — body text, images, tables, headers/footers, and standard formatting map across cleanly. The rare exceptions are documents built around very old VBA macros or unusual embedded OLE objects (like an old Excel 4.0 chart), which may not survive the jump perfectly in every converter.

Is LibreOffice actually free, or is there a catch?

It is genuinely free and open-source with no paid tier, no watermark, and no feature gating — download it from libreoffice.org for Windows, macOS, or Linux. Many organizations use it specifically as a drop-in Word replacement for exactly this kind of format conversion work.

Does Google Docs really convert .doc automatically?

Yes. Upload a .doc file to Google Drive and open it — Google Docs converts it into its own internal format for editing, and File → Download → Microsoft Word (.docx) then exports a proper DOCX file. No software installation is needed at all, just a Google account.

My .doc file has tracked changes and comments — do those survive?

Generally yes, in both Word and LibreOffice, since revision marks and comments are core features both applications understand across format versions. Double-check after conversion if the tracked changes are critical, since very old revision formats occasionally render slightly differently.

Can I batch-convert a whole folder of old .doc files at once?

Microsoft Word and LibreOffice both support command-line/macro-based batch conversion for IT teams migrating large document libraries. For a handful of files, the manual Save As method in any of the three tools above is faster than setting up a batch script.

What should I do with the .docx once I have it?

Edit it normally in any modern word processor, or use the Word to PDF tool on this site to produce a polished, universally-shareable PDF — a common next step once a legacy document has been modernized.

All ToolsDOC to DOCX

DOC to DOCX

Convert legacy .doc files to modern .docx format. Browser conversion isn't possible for this format — follow the free step-by-step methods below.

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DOC to DOCX

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Browser conversion not available for .doc

The legacy .doc binary format requires a full Office engine to parse. Use one of the free methods below — each takes under a minute.

3 Free Ways to Convert

Microsoft Word

Best quality

Open the .doc file → File → Save As → change format to .docx → Save.

LibreOffice Writer (free)

Free & offline

Open the .doc file in LibreOffice Writer → File → Save a Copy → choose .docx format.

Google Docs (free, online)

No install

Go to docs.google.com → Upload the .doc file → it opens automatically → File → Download → Microsoft Word (.docx).

Once you have a .docx file…

📝Convert ODT to DOCX 📄Convert RTF to PDF

Your files never leave your device. All processing happens locally in your browser — nothing is uploaded to our servers.Files are never stored on our servers · No tracking of your file contentsPrivacy Policy

What is DOC to DOCX?

The .doc extension refers to the binary file format Microsoft Word used from Word 97 through Word 2003 — officially the Compound File Binary Format (also called OLE2 or Compound Document File Format). It stores a document as a tree of binary streams: a "WordDocument" stream holding raw text and formatting codes, a separate stream for the table of embedded objects, another for fonts, and so on, all packed together the way an old-school ZIP-less container works. Reverse-engineering that format took Microsoft its own documentation team years to publish (the spec runs past 400 pages), and no reliable JavaScript library exists that can parse it — which is exactly why this page, unlike most of the other tools on this site, cannot process your file directly in the browser.

.docx, introduced in Word 2007, replaced that binary blob with Office Open XML: a ZIP archive containing plain XML files for the document body, styles, fonts, and metadata. It is smaller (ZIP compression), easier to repair if corrupted (you can literally open it and inspect the XML), and it is the format every modern word processor — Google Docs, LibreOffice, Apple Pages, Word for Mac — reads and writes natively.

Because genuinely parsing legacy .doc requires the same compatibility engine Word or LibreOffice ships with, this page walks you through the three practical, completely free ways to get from .doc to .docx today, rather than pretending a lightweight browser script can do something it structurally cannot.

How It Works

The legacy .doc binary format was never publicly specified in a way that a lightweight browser library can parse reliably — doing it properly requires the same rendering and compatibility engine that ships inside Word or LibreOffice. Rather than offer a conversion that silently mangles tables, embedded objects, or unusual formatting, this page gives you three verified free methods below, each of which uses a real Office-compatible engine to do the conversion correctly and takes under a minute.

How to Use

1
Upload your DOC file
Drop an older .doc file onto the upload zone. The legacy Word binary format is read and parsed locally.
2
Convert
Click "Convert to DOCX". The document content, styles, and formatting are converted to the modern Open XML DOCX format.
3
Download the DOCX
Save the .docx file and open it in Microsoft Word 2007 or later, Google Docs, or LibreOffice Writer.
4
Edit freely
The DOCX format supports all modern Word features including tracked changes, comments, and advanced styles.
5
Convert to PDF when done
Once your edits are complete, use the Word to PDF tool to produce a polished PDF output.

Who Uses This Tool

🗄️

Legacy Archives

Upgrade a folder of old .doc files from the 1990s–2000s to modern DOCX so they open cleanly in current software.

🤝

Cross-App Sharing

Convert .doc files before sharing with colleagues who use Google Docs, LibreOffice, or Word for Mac.

📧

Email Attachments

Some email clients and cloud storage warn about legacy .doc files — convert to .docx to avoid compatibility issues.

📝

Template Modernization

Update company document templates from old .doc format to DOCX to take advantage of modern styles and themes.

🔄

PDF Workflow

Convert .doc to .docx first, then use the Word to PDF tool for a reliable, high-quality PDF export.

🏢

IT Migration

IT teams bulk-converting a document library from legacy Office formats to modern DOCX for compatibility.

Why Choose This Tool

Three Free Methods

Word, LibreOffice, and Google Docs all convert .doc to .docx for free — no paid converter needed.

Full Fidelity

Text, images, tables, headers, and common formatting are all preserved during the conversion.

No Upload Needed

Converting locally in Word or LibreOffice means your document never leaves your device.

Smaller File Size

DOCX files use ZIP compression and are typically 20–50% smaller than equivalent .doc binary files.

Modern Features

Once in DOCX format, you can use tracked changes, comments, and advanced Word styles not available in .doc.

PDF-Ready

After conversion, the DOCX integrates seamlessly with our Word to PDF tool for final document delivery.

Also Try

Word to PDF ODT to DOCX PDF to Word HTML to Word Compress PDF Merge PDF

Key Benefits

.docx files are typically 20–50% smaller than the equivalent .doc file
DOCX is read and written natively by Word, LibreOffice, Google Docs, and Apple Pages
Open XML format can be inspected and repaired if a file becomes corrupted
All three conversion methods below are completely free — no Office purchase required
Once converted, chain into our Word to PDF tool for a finished PDF output

Frequently Asked Questions

Also Known As

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