Convert PPT to PPTX — Free Online Converter
Convert Microsoft PowerPoint (.ppt) to PowerPoint Open XML (.pptx) online for free. Fast, secure document conversion with no watermarks or registration.
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How to Convert
Upload your .ppt file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .pptx file when it's ready.
About PPT to PPTX Conversion
PPT is the legacy binary format from PowerPoint 97-2003, using OLE2 compound document structure to store slides, animations, and media in a single binary stream. PPTX is the modern format introduced with Office 2007 — a ZIP archive of XML files following the Office Open XML standard. Converting PPT to PPTX upgrades your presentation from a proprietary binary to a modern, standards-based format with broader compatibility and richer features.
The conversion remaps PPT's binary slide records, text runs, and drawing objects into PPTX's XML-based PresentationML structure. Slides, text, shapes, images, and basic animations are translated to their OOXML equivalents, while the file is repackaged as a compressed ZIP archive.
Why Convert PPT to PPTX?
PPTX is the standard presentation format for all modern software. Microsoft PowerPoint, Google Slides, Apple Keynote, LibreOffice Impress, and every web-based presentation tool imports PPTX natively. PPT files, while still openable, trigger compatibility mode warnings and may render differently in modern software. Converting PPT to PPTX ensures full compatibility with current tools.
PPTX also provides technical advantages: ZIP compression reduces file size (often by 50-70%), the XML internals are self-documenting and recoverable, and the format supports modern features like SmartArt, theme-based styling, advanced animations (morph, 3D), and high-resolution media embedding. Upgrading to PPTX unlocks these features for further editing.
Common Use Cases
- Upgrade legacy PPT archives to the current standard format
- Enable editing in Google Slides, which handles PPTX better than PPT
- Reduce file sizes through PPTX ZIP compression
- Unlock modern editing features (SmartArt, themes, morph transitions) on legacy slides
- Prepare old presentations for upload to cloud-based presentation platforms
How It Works
LibreOffice opens the PPT binary by parsing the OLE2 compound file structure, reading slide records, text runs, drawing objects, and animation sequences. The presentation model is then serialized as PPTX — a ZIP archive containing PresentationML XML files. Each slide becomes a ppt/slides/slideN.xml file, shapes are expressed as DrawingML <a:sp> elements, text runs use <a:r> formatting, and images are stored in ppt/media/. PPT animation sequences are mapped to PPTX timing XML where equivalents exist. The output includes a proper [Content_Types].xml, relationships files, and slide layout/master references.
Quality & Performance
Standard presentation content — text, shapes, images, backgrounds, and basic animations — converts with high fidelity. The PPTX output is visually indistinguishable from the PPT original for typical presentations. PPT-specific features like certain OLE embedded objects and legacy drawing primitives (WMF/EMF) may be converted to more modern representations with minor visual differences. Custom animation effects may simplify to their closest PPTX equivalents. File size typically decreases by 30-60% due to ZIP compression.
Device Compatibility
| Device | PPT | PPTX |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Tips for Best Results
- 1Batch-convert all legacy PPT files to PPTX as a one-time modernization effort
- 2After converting, take advantage of modern features like SmartArt and theme colors
- 3Verify animations in the PPTX — complex custom animations from PPT may simplify
- 4Check embedded objects (charts, OLE) for correct rendering after conversion
- 5Archive the original PPT files as a backup before bulk migration
Related Conversions
PPT to PPTX is a straightforward format upgrade that improves compatibility, reduces file size, and enables modern editing features. There is no reason to keep presentations in PPT format unless a legacy system requires it.