What is a PPTX file?
PPTX is the default file format for Microsoft PowerPoint presentations since Office 2007. It uses the Office Open XML (OOXML) standard — an ISO/IEC international standard — storing all content as compressed XML files inside a ZIP container. PPTX replaced the older binary .ppt format, making presentations more interoperable across applications and easier to recover if partially corrupted.
A PPTX file contains slides with text boxes, images, charts, SmartArt, animations, slide transitions, speaker notes, and embedded multimedia (video, audio, 3D models). Because it is a ZIP archive, you can rename .pptx to .zip and explore its internal XML structure directly.
How to open PPTX files
- Microsoft PowerPoint (Windows, macOS) — Full editing and native format
- Google Slides (Web) — Free online editing; import/export PPTX
- LibreOffice Impress (Windows, macOS, Linux) — Free, strong PPTX compatibility
- Apple Keynote (macOS, iOS) — Import support with conversion
- WPS Presentation (Windows, Linux, Android) — Free alternative
Technical specifications
| Property | Value |
|---|---|
| Format | Office Open XML (OOXML) |
| Internal structure | ZIP archive containing XML + media files |
| Standard | ISO/IEC 29500, ECMA-376 (4th edition) |
| Slide size default | Widescreen 13.33” × 7.5” (16:9) |
| Max slide size | 56” × 56” |
| Embedded content | Video, audio, images, 3D models, OLE objects |
| Magic bytes | 50 4B 03 04 (ZIP signature, shared with .docx, .xlsx) |
Common use cases
- Business presentations: Board meetings, sales pitches, quarterly reports, and investor decks
- Education: University lectures, training materials, and e-learning course slides
- Conference talks: Speaker presentations with slide animations and embedded demos
- Marketing: Product launch decks, brand guidelines, and pitch materials
- Templates: Reusable slide designs shared across teams via SharePoint or OneDrive
PPTX internal structure
Renaming a PPTX to ZIP and extracting reveals the internal layout:
presentation.zip/
├── [Content_Types].xml
├── _rels/
├── ppt/
│ ├── presentation.xml ← Master settings, slide order
│ ├── slides/
│ │ ├── slide1.xml ← Individual slide content
│ │ └── slide2.xml
│ ├── slideLayouts/ ← Layout templates
│ ├── slideMasters/ ← Master slide designs
│ ├── theme/ ← Color and font themes
│ └── media/ ← Embedded images and videosThis open structure makes it possible to programmatically generate or modify PPTX files using libraries like python-pptx without opening PowerPoint.
Generating PPTX programmatically
from pptx import Presentation
from pptx.util import Inches, Pt
prs = Presentation()
slide_layout = prs.slide_layouts[1] # Title and Content layout
slide = prs.slides.add_slide(slide_layout)
slide.shapes.title.text = "Q1 Results"
slide.placeholders[1].text = "Revenue up 23% year-over-year"
prs.save("report.pptx")The python-pptx library enables automated report generation, data-driven slide decks, and batch presentation creation from templates.
PPT vs PPTX
| Feature | PPTX | PPT (legacy) |
|---|---|---|
| Format | Open XML (ZIP + XML) | Binary |
| File size | Often smaller | Often larger |
| Corruption recovery | Easier (XML is inspectable) | Harder |
| Standard | ISO/IEC 29500 | Proprietary |
| Interoperability | Better | Limited |
Always save in PPTX unless the recipient specifically requires the legacy PPT format (Office 2003 or older).
Presentation tips for compatibility
When sharing PPTX files across platforms: embed fonts (File → Options → Save → Embed fonts) to ensure custom typefaces display correctly on machines that don’t have them installed. Flatten complex animations before sharing if recipients use LibreOffice or Google Slides, as animation fidelity varies. Export to PDF for read-only sharing where editing is not needed.