PPT to PPTX is handled by our office engine, which rewrites the old binary PowerPoint container as Office Open XML and can expose legacy import problems.
From real runs
| Element | Result | What happens |
|---|---|---|
| Package format | Changed | The output became a valid PPTX zip with presentation.xml, slide layouts, a theme file, and slide relationships. |
| Legacy binary streams | Changed | The OLE compound PPT stream was decoded by our office engine, then rewritten without preserving the original binary record structure. |
| Slide text | Lost | Our generated PPT fixture converted to placeholders without the Feedback Atlas text, so this route needs visual spot checks. |
| Slide count | Changed | Our office engine produced one PPTX slide from the legacy fixture even though the richer PPTX source had two slides before down-saving. |
| Master layouts | Changed | A modern PowerPoint theme and default layout set were written, not the exact old master-slide records from the PPT file. |
| Animations | Changed | Old transition and animation records may be simplified or removed during the binary-to-XML rewrite. |
| Macros | Lost | This route writes .pptx, so any VBA project from a legacy macro-enabled presentation is not preserved. |
The output became a valid PPTX zip with presentation.xml, slide layouts, a theme file, and slide relationships.
The OLE compound PPT stream was decoded by our office engine, then rewritten without preserving the original binary record structure.
Our generated PPT fixture converted to placeholders without the Feedback Atlas text, so this route needs visual spot checks.
Our office engine produced one PPTX slide from the legacy fixture even though the richer PPTX source had two slides before down-saving.
A modern PowerPoint theme and default layout set were written, not the exact old master-slide records from the PPT file.
Old transition and animation records may be simplified or removed during the binary-to-XML rewrite.
This route writes .pptx, so any VBA project from a legacy macro-enabled presentation is not preserved.
We converted our PowerPoint PPT sample (449 KB) with Office engine on 2026-09-11. It took 520 ms and produced a 26 KB PowerPoint PPTX file, 94% smaller than the input. The engine raised no warnings.
Input · sample.ppt · 449 KB
OLE2 compound document (legacy Office binary)
Output · sample.pptx · 26 KB
Presentation with 1 slide, 0 notes pages, 0 media files
LibreOffice
soffice --headless --convert-to pptx legacy.ppt --outdir .Run a visual comparison afterward; our converter also lost text from the generated legacy fixture, so check yours.
The HTTP API and the MCP server run the exact engine this page uses (Office engine); the response carries the same warnings the web converter shows. Check support first with GET /api/v1/pairs?from=ppt&to=pptx.
curl -X POST https://filetypeconverters.com/api/v1/convert \
-H "Authorization: Bearer $FTC_API_KEY" \
-F "file=@input.ppt" -F "from=ppt" -F "to=pptx" \
--output output.pptx/convert/ppt-to-pdf if the goal is review or archival viewing rather than editing in modern PowerPoint.Our office engine has to import old binary records before writing Office XML. In our fixture, that import produced placeholders without the original slide text, so old decks need manual review.
No. The target is .pptx, which is not the macro-enabled PowerPoint format. Keep or separately audit the original if macros are part of the file.
It creates an editable PPTX package when our office engine can import the slide objects. Edibility is not a guarantee of fidelity for very old or damaged PPT files.