File extension

.pptx

Office Open XML Presentation (PPTX)

.pptx files are Office Open XML presentations: the modern Microsoft PowerPoint format, a ZIP package (OPC) of XML parts and media describing slides, layouts, and embedded content.

Known meanings

Formats and reference material for .pptx

Office Open XML Presentation (PPTX)

ZIP-packaged XML presentation format (Microsoft PowerPoint / ECMA-376 / ISO 29500)

  • documents
  • Microsoft / ECMA / ISO
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Details

Format notes

Office Open XML Presentation (PPTX)

PPTX is the default presentation format of Microsoft PowerPoint since PowerPoint 2007 and the successor to the legacy binary .ppt. It is part of Office Open XML (OOXML), standardized as ECMA-376 and ISO/IEC 29500. As with DOCX and XLSX, the format is an open, inspectable package of XML rather than an opaque binary file.

A PPTX is a ZIP archive following the Open Packaging Conventions (OPC), so it starts with the usual ZIP signature PK. Each slide is a separate XML part under ppt/slides/ (for example ppt/slides/slide1.xml), while slide layouts, slide masters, themes, and notes live in their own parts. Images, audio, and video are stored as separate files under ppt/media/, and .rels files declare the relationships between parts. Related extensions are .pptm (macro-enabled), .ppsx (slide show), and .potx (template).

Interoperability And Tooling

PPTX is read and written by PowerPoint, LibreOffice Impress, Google Slides, Apple Keynote (import/export), and many libraries, which makes it a practical exchange format for editable presentations. Because it is ZIP plus XML, tools can generate or inspect slides without PowerPoint. Layout and animation fidelity can still vary between applications, and fonts that are not embedded or installed are substituted. The media type is application/vnd.openxmlformats-officedocument.presentationml.presentation.

Preservation And Security Notes

For long-term preservation, keep the editable PPTX and consider a PDF rendition as a fixed-layout companion. Presentations can contain linked or embedded external content and, in the .pptm variant, VBA macros, so untrusted files should be opened with macros disabled and external content blocked. When extracting parts from the ZIP container, guard against decompression bombs and path traversal.

Further Reading

  • PPTX file format specification (Microsoft): https://learn.microsoft.com/openspecs/office_standards/ms-pptx/
  • ECMA-376 (Office Open XML): https://www.ecma-international.org/publications-and-standards/standards/ecma-376/