Word conversion
Convert DOC and DOCX in .NET
Read Word 97–2003 DOC files, convert them to DOCX, or deliver supported DOC output from .NET with explicit fidelity and preservation diagnostics.
DOC and DOCX summary
- Input
- DOC
- Output
- DOCX
- Package
- OfficeIMO on NuGet
- Runs on
- .NET on Windows, Linux, and macOS
- Microsoft Office
- Not required
- License
- MIT
DOC and DOCX do not share every feature. Conversion reports approximated, preserved, dropped, or blocked content instead of hiding loss.
Explore all conversion guidesPractical steps
Convert a DOC file to DOCX with OfficeIMO
Analyze the source, choose an accepted compatibility policy, and create a modern DOCX file without Microsoft Word.
- InstallAdd the OfficeIMO NuGet package to the application.
- AnalyzeInspect the conversion report when the workflow has fidelity requirements.
- ConvertCall OfficeConverter.Convert with the source DOC and destination DOCX paths.
- ReviewRecord or reject findings according to the application's document policy.
Use OfficeIMO for file-to-file conversion of Word 97–2003 documents without Microsoft Word or COM automation. OfficeIMO.Word owns the Word object model and its native DOC support. The normal Word engine detects the source format, projects supported DOC content into the OfficeIMO object model, and records features that need approximation, visual fallback, preservation, or rejection.
DOC to DOCX
using OfficeIMO;
OfficeConversionReport preview =
OfficeConverter.Analyze("archive.doc", "archive.docx");
OfficeConversionReport result =
OfficeConverter.Convert("archive.doc", "archive.docx");
For an unattended archive job, use the preview report to decide whether the application accepts every finding before it creates the destination. Keep the report beside migration logs when auditability matters.
DOCX to DOC
The same API supports the reverse direction for the documented native DOC subset:
using OfficeIMO;
OfficeConversionReport result =
OfficeConverter.Convert("contract.docx", "contract.doc");
DOC has a smaller feature vocabulary than DOCX. Modern charts, content controls, custom XML, advanced drawing, or other features may require a selected fallback or may be blocked. OfficeIMO does not label a lossy result as fully native.
When to use each direction
Choose DOC to DOCX for archive modernization, search ingestion, continued editing, and integration with modern Office workflows. Choose DOCX to DOC only when a downstream system genuinely requires the legacy format and the compatibility report meets that system's needs.
For the current feature-level evidence, see Word compatibility. For authoring and review APIs after conversion, use the Word guide.