Quick answer
- PPTX is an XML-based office presentation format that stores slides and related resources in a ZIP package, with VBA macros requiring a different extension such as PPTM.
- Open a PPTX file with Microsoft PowerPoint on Windows or macOS. On a phone or tablet, install PowerPoint and open the file there. PowerPoint for the web also supports opening and editing PPTX presentations. PowerPoint 2007 and 2010 open PPTX without a special add-in or loss of functionality.
- PPTX is the macro-free PowerPoint subtype, but macro-free does not mean inert. A PPTX package may contain an ActiveX control, and presentations may reference external images, linked media, hyperlinks, templates, or data connections. Office blocks external content by default because it can disclose information or, in documented linked-media cases, enable malicious script execution. Enable it only for trusted files. The registered subtype may contain personal information and provides no ECMA-376 or ISO/IEC 29500 encryption mechanism. Encrypted OOXML documents use mechanisms outside this registered subtype.
PPTX File: What It Is, How to Open It, and Conversion Limits
Introduced with Office 2007, PPTX is PowerPoint's Open XML presentation format. It belongs to the ECMA-376 and ISO/IEC 29500 Office Open XML family. Its package can contain presentation.xml, separate slide parts, layouts, masters, themes, notes, comments, and other Open Packaging Convention parts.
Saving PPTX as PowerPoint 97–2003 PPT can reduce fidelity or editing functionality; Compatibility Checker identifies affected content, and SmartArt may become a picture while animations attached to converted text may be lost. PPTX-to-ODP conversion is also not lossless and can alter animations, transition sounds, comments, themes, ActiveX controls, and advanced graphics.
Open a file
Open a PPTX file with Microsoft PowerPoint on Windows or macOS. On a phone or tablet, install PowerPoint and open the file there. PowerPoint for the web also supports opening and editing PPTX presentations. PowerPoint 2007 and 2010 open PPTX without a special add-in or loss of functionality.
Open a PPTX file with Microsoft PowerPoint on Windows or macOS. On a phone or tablet, install PowerPoint and open the file there. PowerPoint for the web also supports opening and editing PPTX presentations. PowerPoint 2007 and 2010 open PPTX without a special add-in or loss of functionality.
Saving PPTX as PowerPoint 97–2003 PPT can reduce fidelity or editing functionality; Compatibility Checker identifies affected content, and SmartArt may become a picture while animations attached to converted text may be lost. PPTX-to-ODP conversion is also not lossless and can alter animations, transition sounds, comments, themes, ActiveX controls, and advanced graphics.
File safety
PPTX is the macro-free PowerPoint subtype, but macro-free does not mean inert. A PPTX package may contain an ActiveX control, and presentations may reference external images, linked media, hyperlinks, templates, or data connections. Office blocks external content by default because it can disclose information or, in documented linked-media cases, enable malicious script execution. Enable it only for trusted files. The registered subtype may contain personal information and provides no ECMA-376 or ISO/IEC 29500 encryption mechanism. Encrypted OOXML documents use mechanisms outside this registered subtype.
Do not open the file when its source, double extension, or actual contents do not match what you expected.
Converters
Saving PPTX as PowerPoint 97–2003 PPT can reduce fidelity or editing functionality; Compatibility Checker identifies affected content, and SmartArt may become a picture while animations attached to converted text may be lost. PPTX-to-ODP conversion is also not lossless and can alter animations, transition sounds, comments, themes, ActiveX controls, and advanced graphics.
Work from a copy, then compare image quality, metadata, and layout after conversion.
Frequently asked questions
What is a PPTX file format and what is it used for?
PPTX is PowerPoint's XML-based presentation format, introduced with Office 2007. It stores slides and related parts such as layouts, masters, themes, notes, and comments inside a ZIP-based Open Packaging Convention package.
How do I open a PPTX file?
Open it with Microsoft PowerPoint. PowerPoint on Windows and macOS supports PPTX, as do PowerPoint mobile apps and PowerPoint for the web.
How do I open a PPTX file on Windows?
Open the file in Microsoft PowerPoint for Windows. PowerPoint 2007 and 2010 can open PPTX without a special add-in or loss of functionality.
How do I open a PPTX file on a Mac?
Use Microsoft PowerPoint for macOS, which supports opening PPTX presentations.
How do I open a PPTX file on a mobile phone or tablet?
Install Microsoft PowerPoint on the mobile device and open the PPTX file in the app.
Can I open and edit a PPTX file in PowerPoint for the web?
Yes. PowerPoint for the web supports opening PPTX files for editing.
Why will my PPTX file not open even though it has the correct extension?
The .pptx extension alone does not establish that the file contains a valid PPTX package. Its registered signature is 50 4B 03 04, but that ZIP signature is not unique to PPTX. Try PowerPoint for the web to check whether the package opens at all.
PPTX versus PPT: which presentation format should I use?
Use PPTX for the XML-based PowerPoint format. Use PPT only when the older PowerPoint 97–2003 format is required, because saving PPTX as PPT can reduce fidelity or editing functionality and may convert unsupported content.
What can change when I convert PPTX to ODP?
PPTX-to-ODP conversion is not lossless. Formatting can change, and affected features can include color and scaling animations, transition sounds, comments, themes, ActiveX controls, and some advanced graphics.
Can a PPTX file contain macros, and is an emailed PPTX automatically safe?
PPTX is the macro-free subtype; VBA macros require a macro-enabled extension such as PPTM. However, PPTX may contain an ActiveX control and reference external content, so an emailed PPTX should not be considered safe solely because it cannot contain VBA macros.
How should I assess PPTX external links and ActiveX controls before enabling content?
Treat unexpected ActiveX controls, linked media, external images, templates, hyperlinks, and data connections cautiously. Enable content only when both the PPTX file and its external content are trusted.
What are the official PPTX MIME type and file signature?
The registered media type is application/vnd.openxmlformats-officedocument.presentationml.presentation. IANA records the signature 50 4B 03 04, but it is a generic ZIP signature and is not unique to PPTX.
Related formats
Sources
Media Type Registration: application/vnd.openxmlformats-officedocument.presentationml.presentation · Internet Assigned Numbers Authority (IANA)
ECMA-376 — Office Open XML file formats · Ecma International
Save your presentation file · Microsoft Support
Open XML Formats and file name extensions · Microsoft Support
Structure of a PresentationML document · Microsoft Learn
File formats that are supported in PowerPoint · Microsoft Support
About compatibility mode in PowerPoint · Microsoft Support
Use PowerPoint to save or open a presentation in the OpenDocument Presentation (.odp) format · Microsoft Support
Block or unblock external content in Office documents · Microsoft Support