DOC to DOCX Converter
Modernise an old Word 97-2003 (DOC) file into the current DOCX format.
Complete the security check to begin
About Converting DOC to DOCX
Converting .doc to .docx upgrades a legacy Word 97-2003 binary file to the modern Office Open XML format Microsoft has used since Word 2007. Under the hood .docx is a ZIP archive of XML parts, which makes it dramatically smaller, far less likely to corrupt, and readable by virtually every current word processor including Google Docs, Pages and LibreOffice.
This conversion keeps your document fully editable — unlike exporting to PDF, you get a file you can keep working on. PrivConvert performs the upgrade in memory through the LibreOffice engine, preserving styles, tables, lists and images, then deletes the source immediately.
Common use cases
- Modernising an archive of old .doc files so they open without compatibility warnings
- Preparing a legacy document for upload to Google Docs or Microsoft 365, which prefer .docx
- Reducing file size — .docx is compressed and typically much smaller than the equivalent .doc
- Fixing documents that throw "file is corrupt" errors in newer Word versions
- Standardising a team on a single modern format before collaborative editing
Tips for best results
- After converting, review any auto-numbered lists — very old .doc numbering schemes occasionally renumber when upgraded.
- Legacy WordArt and some pre-2007 drawing objects may be redrawn with their modern equivalents.
- If the document contains tracked changes, accept or reject them before converting for the cleanest result.
- The conversion is lossless for ordinary text and formatting; only deprecated features are modernised.
How to Convert DOC to DOCX Online
Turning a DOC file into DOCX is straightforward here — upload, convert, download. What you gain with DOCX: fully editable.
Drag and drop your file into the upload area, click to browse your device, or paste a URL to a file hosted online. You can upload files up to 250 MB and batch convert up to 20 files at once.
Once uploaded, the conversion from DOC to DOCX starts automatically. The process runs entirely in an isolated environment - your data never leaves the secure pipeline.
Your converted file is ready instantly. Click the download button to save it to your device. The file is deleted from memory immediately after download.
Why choose PrivConvert?
Converting DOC to DOCX should not mean handing a stranger a permanent copy of your data. PrivConvert processes everything in memory and forgets it instantly.
Every conversion runs in its own locked-down process with no network access, so files can never leak or interfere with one another.
Your files are handled entirely by automated code. No staff, partner or AI model ever reads, stores or trains on your data.
Files are processed in volatile memory (RAM) and purged the instant your download is ready — nothing is ever written to disk, cached or backed up.
Every upload and download is protected with TLS 1.3, so your document cannot be intercepted on the way to the server or back to you.
DOC vs DOCX - Format Comparison
| Feature | DOC | DOCX |
|---|---|---|
| File extension | .doc | .docx |
| Supported by PrivConvert | Yes (as input) | Yes (as output) |
| Privacy-safe conversion | In-memory, zero storage | |
| Max file size | 250 MB per file | |
| Batch support | Up to 20 files simultaneously | |
Trusted by thousands of users
Professionals reach for PrivConvert when the document they are converting is sensitive and cannot be left sitting on someone else’s server.