File types · Explainer

The PPTX file (.pptx)

A PPTX file is a PowerPoint presentation: a ZIP package of XML files holding the slides, their layouts and masters, speaker notes and media. This guide explains what's inside one, how it differs from PPT, PDF and Keynote, the quirks worth knowing, and has free sample PPTX files to download for testing.

Sample PPTX filesPut a PPTX file online

At a glance

Full name
Office Open XML presentation (PresentationML)
Extensions
.pptx
MIME type
application/vnd.openxmlformats-officedocument.presentationml.presentation
Kind
Binary: a ZIP package of XML parts and media files
Standard
ECMA-376 and ISO/IEC 29500; created by Microsoft
First released
2006 as ECMA-376; PowerPoint's default format since PowerPoint 2007
Opens with
PowerPoint, Keynote, Google Slides, LibreOffice Impress
Magic number
50 4B 03 04, the ZIP signature; a ppt/presentation.xml part inside marks it as PowerPoint
Slide size
Default 16:9, 13.333 × 7.5 in; the older Standard 4:3 is 10 × 7.5 in
Macros
Not allowed; macro-enabled presentations use .pptm

The basics

What is a PPTX file?

PPTX is the file format PowerPoint saves presentations in. It replaced the binary PPT format as PowerPoint's default in PowerPoint 2007, and it's part of the Office Open XML standard (ECMA-376, ISO/IEC 29500), so Keynote, Google Slides, LibreOffice Impress and many libraries read and write it too.

A PPTX holds a deck of slides and everything around them: the layouts and master that give the slides their look, speaker notes, comments, pictures, charts with their data, embedded audio and video, transitions and animations. It's made for editing and presenting; to hand out a deck that looks the same everywhere, people usually send a PDF.

  • It's a package. Each slide, layout, master, notes page and media file is a separate part inside a ZIP archive.
  • Slides inherit. A slide takes its placeholders from a layout, which takes its styles from a master, which takes colours and fonts from a theme.
  • It doesn't carry fonts by default. If the computer showing it lacks a font, another one is substituted and text can reflow or overflow.

Anatomy

What's inside a PPTX file

Rename a .pptx to .zip and you can open it like any archive. Inside are XML parts that point to each other through relationship files. Our sample-minimal.pptx has one slide and only the parts that slide needs; here they are, part by part.

sample-minimal.pptx (file list and XML)
$ unzip -l sample-minimal.pptx
  Length  Name
     983  [Content_Types].xml
     301  _rels/.rels
     525  ppt/presentation.xml
     572  ppt/_rels/presentation.xml.rels
    1065  ppt/slides/slide1.xml
     310  ppt/slides/_rels/slide1.xml.rels
     514  ppt/slideLayouts/slideLayout1.xml
     310  ppt/slideLayouts/_rels/slideLayout1.xml.rels
    1314  ppt/slideMasters/slideMaster1.xml
     445  ppt/slideMasters/_rels/slideMaster1.xml.rels
    1982  ppt/theme/theme1.xml

First 4 bytes: 50 4b 03 04  (PK..)

ppt/presentation.xml:
<p:presentation …>
  <p:sldMasterIdLst><p:sldMasterId id="2147483648" r:id="rId1"/></p:sldMasterIdLst>
  <p:sldIdLst><p:sldId id="256" r:id="rId2"/></p:sldIdLst>
  <p:sldSz cx="12192000" cy="6858000"/>
  <p:notesSz cx="6858000" cy="9144000"/>
</p:presentation>

ppt/slides/slide1.xml, the text box:
<p:sp>
  <p:nvSpPr><p:cNvPr id="2" name="Text 1"/><p:cNvSpPr txBox="1"/><p:nvPr/></p:nvSpPr>
  <p:spPr>
    <a:xfrm><a:off x="914400" y="2286000"/><a:ext cx="10363200" cy="1828800"/></a:xfrm>
    <a:prstGeom prst="rect"><a:avLst/></a:prstGeom>
  </p:spPr>
  <p:txBody>
    <a:bodyPr/>
    <a:p><a:r><a:rPr lang="en-GB" sz="4400" b="1"/><a:t>Hello, world.</a:t></a:r></a:p>
    <a:p><a:r><a:rPr lang="en-GB" sz="2000"/><a:t>Sample PPTX from 99helpers.com/…</a:t></a:r></a:p>
  </p:txBody>
</p:sp>
  1. 150 4b 03 04

    The ZIP signature

    Every PPTX starts with the ZIP local file header, "PK". That's why tools that look only at the first bytes report it as a ZIP archive, exactly as with DOCX and XLSX.

  2. 2[Content_Types].xml

    The content types

    Says which part is the presentation, which are slides, layouts, masters and themes. PowerPoint won't open a package without it.

  3. 3_rels/.rels

    The entry point

    Points to ppt/presentation.xml. Every part that refers to others has its own .rels file in a _rels folder next to it.

  4. 4<p:sldIdLst>

    The slide list

    The order of the slides. Each entry has an ID and a relationship ID that leads to the slide's part, so reordering slides only changes this list, not the file names.

  5. 5<p:sldSz cx="12192000" cy="6858000"/>

    The slide size

    In EMUs (English Metric Units): 914,400 per inch, 360,000 per centimetre. 12,192,000 × 6,858,000 is 13.333 × 7.5 inches, the 16:9 widescreen size. A 4:3 deck has cx="9144000", 10 inches.

  6. 6ppt/slides/slide1.xml

    A slide

    A tree of shapes (p:spTree): text boxes, placeholders, pictures, tables, charts and groups. It names its layout in its own .rels file.

  7. 7ppt/slideLayouts/slideLayout1.xml

    A slide layout

    Title Slide, Title and Content, Two Content and so on. Layouts hold the placeholders a slide inherits. This one is Blank.

  8. 8ppt/slideMasters/slideMaster1.xml

    The slide master

    The background and the default text styles for titles, body text and everything else. Every layout belongs to a master; a deck can have several.

  9. 9ppt/theme/theme1.xml

    The theme

    Twelve theme colours, a heading and a body font, and fill, line and effect styles. Shapes that use theme colours change when you switch themes.

  10. 10<a:off x="914400" y="2286000"/>

    Position and size

    The shape's top-left corner (1 inch from the left, 2.5 from the top) and its size, all in EMUs. Placeholders often leave this out and take the position from their layout.

  11. 11<a:rPr lang="en-GB" sz="4400" b="1"/>

    A text run

    Text is in paragraphs (a:p) of runs (a:r). Font sizes are in hundredths of a point: 4400 is 44 pt. a: elements come from DrawingML, shared with Word and Excel graphics.

Under the hood

The parts of a typical PPTX

A deck saved by PowerPoint, or our sample-presentation.pptx, has many more parts than the minimal file above. The usual ones:

PartWhat it holds
ppt/presentation.xmlThe slide list, the masters, the slide and notes sizes.
ppt/slides/slide1.xml …One part per slide: shapes, text, tables, transitions and animation timings.
ppt/slideLayouts/, ppt/slideMasters/The layouts (11 in PowerPoint's default design) and their master.
ppt/theme/theme1.xmlTheme colours, fonts and effects.
ppt/notesSlides/, ppt/notesMasters/Speaker notes, one part per slide that has them, and their master.
ppt/media/Pictures, audio and video, in their original formats. A picture used on ten slides is stored once.
ppt/charts/, ppt/embeddings/Charts as DrawingML XML, each with an embedded .xlsx workbook holding its data.
ppt/comments/ or ppt/comments/modernComment_…Review comments; newer PowerPoint versions use a threaded format.
docProps/core.xml, docProps/app.xmlTitle, author, dates; the app that saved it, slide and note counts.
ppt/presProps.xml, ppt/viewProps.xmlSlide show settings and the last view used in the editor.

Getting at the content without PowerPoint

Copy the file, change .pptx to .zip and open it: pictures and videos are in ppt/media/ at their original size. In code, python-pptx (Python), Apache POI (Java) and the Open XML SDK (.NET) read and write the parts for you.

Variants

PPTX, PPSX, PPTM, POTX and slide sizes

ExtensionWhat it is
.pptxPresentation. Can't contain macros.
.pptmPresentation with VBA macros. Same structure plus a vbaProject.bin part.
.ppsxPowerPoint Show: the same content, but double-clicking it starts the slide show instead of the editor.
.potxTemplate: opening it starts a new presentation based on its masters and layouts.
.ppamPowerPoint add-in, which contains macros.
`.ppt`The binary format of PowerPoint 97 to 2003.
.odpOpenDocument Presentation, LibreOffice Impress's own format, an ISO standard.

The ISO standard has a Transitional and a Strict flavour, as for DOCX and XLSX; almost all PPTX files are Transitional. Slide size is a setting, not a variant: new decks are 16:9 widescreen (13.333 × 7.5 in), and Standard 4:3 (10 × 7.5 in) is still offered. Changing it later makes PowerPoint ask whether to Maximize the content, which can push it off the slide, or Ensure Fit, which shrinks it.

Comparison

PPTX vs PPT, PDF, Keynote and Google Slides

PPTXPPTPDFKeynote (.key)Google Slides
StructureZIP of XML and mediaBinary records in an OLE2 fileBinary objects and streamsApple's own package formatOnline only; exports PPTX or PDF
Made forEditing and presentingEditing and presentingHanding out fixed pagesEditing and presenting on Apple devicesEditing together in a browser
Open standardYes (ISO/IEC 29500)Documented as [MS-PPT]Yes (ISO 32000)NoNo
Embedded videoYesNo: video is linkedPossible, rarely playedYesFrom YouTube or Drive
Speaker notesYesYesOnly if printed into the pagesYesYes
Opens in a browserNo, it downloadsNoYesNoYes

Keynote and Google Slides both open PPTX files and export to PPTX, but each has its own layout engine, fonts and effects, so complex animations, SmartArt and some transitions change or disappear on the way. For a deck that must look identical everywhere, export a PDF.

Troubleshooting

Common PPTX problems and how to fix them

  • Fonts look different on another computer. The font wasn't installed there and isn't in the file. Use common fonts, embed them (PowerPoint: File, Options, Save, "Embed fonts in the file"), or present from a PDF.
  • A video won't play. Either it was linked rather than embedded and the file didn't come along, or the other device can't decode it. Insert video as MP4 (H.264 video, AAC audio), which PowerPoint recommends, and check it's embedded.
  • The file is huge. Almost always pictures and video at full size. Use Compress Pictures, and File, Info, Compress Media in PowerPoint for Windows.
  • "PowerPoint found a problem with content … can attempt to repair." The package has a broken part, often from a tool that generated it. Repair removes what it can't read; renaming a copy to .zip lets you rescue the media.
  • Slides look stretched or cut off after changing the size. Switching between 4:3 and 16:9 rescales content. Undo, and choose Ensure Fit instead of Maximize, or the other way round.
  • It opens read-only with a yellow bar. That's Protected View for files from the internet or email. Choose Enable Editing if you trust the source.

How to

How to open, edit and convert a PPTX file

  • PowerPoint on Windows and Mac, PowerPoint for the web (free with a Microsoft account) and the PowerPoint apps for iPhone, iPad and Android.
  • Without PowerPoint: Keynote on Mac, iPhone and iPad opens PPTX and exports it; Google Slides opens PPTX files uploaded to Google Drive; LibreOffice Impress (free, Windows, Mac, Linux) opens and saves them.
  • In a browser: browsers can't display PPTX files, so a link to one downloads it. To have a deck viewed in the browser, export it as PDF.
  • Convert to PDF: in PowerPoint, File, Export or Save As, PDF, where you can also choose to include notes pages. On a server: soffice --headless --convert-to pdf deck.pptx.
  • Convert to video: PowerPoint's File, Export, Create a Video records the slides, timings and narration as an MP4.
  • Convert from PPT: open the old file and Save As PowerPoint Presentation (.pptx), or soffice --headless --convert-to pptx old.ppt.

Security

Is it safe to open a PPTX? And what does it reveal?

A .pptx can't hold VBA macros; macro-enabled decks are .pptm or .ppsm, and Office on Windows has blocked macros in files from the internet by default since 2022. Risks that remain:

  • Links and action settings. A shape can open a web page or start a program when it's clicked or hovered over. PowerPoint warns before running a program; don't accept warnings for files you didn't expect.
  • Embedded objects. OLE objects inside a slide can contain other documents or files that run when double-clicked.
  • Phishing. A slide showing a fake "document" with a sign-in link is a common trick.

Presentations also carry more than the audience sees:

  • Speaker notes, which travel with the file even when you only meant to share the slides.
  • Hidden slides, comments and author names in the document properties.
  • Cropped parts of pictures and content placed off the edge of a slide, still in the file.

Before sending a deck outside your organisation, run PowerPoint's Document Inspector (File, Info, Check for Issues, Inspect Document) to remove notes, comments and hidden data, or send a PDF without notes.

Free downloads

Sample PPTX files to download

Free sample PowerPoint presentations for testing converters, previews, parsers and uploads. Each one is a valid ZIP package with well-formed XML, opens with python-pptx and converts to PDF with LibreOffice.

sample-presentation.pptx · 183.5 KBDownload

Browsers can't show this kind of file in a page. Download it to open it in the app it belongs to.

What's inside sample-presentation.pptx

Browsers can't preview PPTX files, so download it and open it in PowerPoint, Keynote, Google Slides or LibreOffice. These are the parts to look for, and where they live in the package.

  1. Seven 16:9 slides on five layouts

    Title Slide, Title and Content, Two Content and Title Only, all from one master in ppt/slideMasters/.

  2. Bullets with levels

    Slide 2: paragraphs with indent levels, whose bullet characters and sizes come from the master's body style.

  3. A table

    Slide 4: a five-row DrawingML table (a:tbl) with a built-in table style.

  4. A chart with its data

    Slide 5: a clustered column chart in ppt/charts/chart1.xml, with its numbers in an embedded workbook, ppt/embeddings/Microsoft_Excel_Sheet1.xlsx.

  5. A picture with alt text

    Slide 6: a 1280 × 720 JPEG stored as ppt/media/image1.jpg, with a description for screen readers.

  6. A hyperlink

    Slide 7: the link text is on the slide; its address is in ppt/slides/_rels/slide7.xml.rels, marked external.

  7. Notes, slide numbers and transitions

    Speaker notes on every slide in ppt/notesSlides/, a slide-number field, and a fade transition stored in each slide's XML.

  8. Document properties

    Title, author, subject, keywords and a comment in docProps/core.xml, shown under File, Info.

All sample PPTX files

  • Seven-slide sample deck

    sample-presentation.pptx · 183.5 KB (187,945 bytes)

    A 16:9 deck: title slide, bullets, two columns, a table, a chart with an embedded workbook, a picture, a hyperlink, speaker notes on every slide, slide numbers and fade transitions.

    • Testing converters and previews
    • Checking parsers against a typical deck
    Download

  • Minimal PPTX, eleven parts

    sample-minimal.pptx · 4.6 KB (4,720 bytes)

    Written by hand: one slide with one text box, one blank layout, a master and a compact theme. No document properties, notes or media. It's the file in the anatomy above.

    • Parser tests: don't assume optional parts exist
    • Learning the package structure
    Download

  • Standard 4:3 deck

    sample-4x3.pptx · 31.7 KB (32,459 bytes)

    Two slides at the older Standard size, 10 × 7.5 inches (sldSz 9144000 × 6858000), with notes.

    • Testing previews and thumbnails with a non-16:9 aspect ratio
    • Letterboxing on widescreen displays
    Download

  • Embedded video

    sample-video.pptx · 306.7 KB (314,081 bytes)

    One slide with a 4-second 640 × 360 MP4 (H.264 video, AAC audio, 25 fps) embedded in ppt/media/, and a PNG poster frame shown before it plays.

    • Testing media extraction and playback in viewers
    • Checking converters that drop or keep video
    Download

  • 1 MB PPTX file

    sample-1mb.pptx · 1 MB (1,048,576 bytes)

    Three slides, each filled by a 1920 × 1080 JPEG, padded to exactly 1,048,576 bytes (1 MiB) with whitespace in docProps/app.xml.

    • Upload limits and timeouts
    • Image extraction and thumbnail generation
    Download

Ways to test with them

  • File type detection: all five start with the ZIP signature. A detector that reports application/zip instead of the PPTX type isn't looking for ppt/presentation.xml inside.
  • Slide size: thumbnails of sample-presentation.pptx should be 16:9 and of sample-4x3.pptx 4:3. Code that assumes one aspect ratio will stretch the other.
  • Media: sample-video.pptx references one MP4 through two relationships, a standard video one and a Microsoft media one. Extraction code should export the file once.
  • Conversion fidelity: convert sample-presentation.pptx to PDF and check the table, the chart, the picture, the slide numbers and the link.
  • Upload limits: sample-1mb.pptx is exactly 1,048,576 bytes, so you can test a limit right at the boundary.

Free to use for testing, teaching and demos, commercially or not, with no attribution needed. A link back to this page is always appreciated.

Put it online

Have a PPTX file? Give it a link.

Drop a PowerPoint presentation on 99helpers and it gets its own link. Browsers can't display PPTX files, so visitors download it and open it in PowerPoint, Keynote or Google Slides; to have a deck viewed in the browser, upload a PDF version.

Put a PPTX file online

Questions

PPTX files, frequently asked

What is a PPTX file?

A PowerPoint presentation in the Office Open XML format, PowerPoint's default since 2007. It's a ZIP package of XML files and media holding the slides, layouts, notes, pictures and video.

What's the difference between PPT and PPTX?

PPT is the binary format of PowerPoint 97 to 2003. PPTX is XML in a ZIP: smaller, an open standard, able to embed video, and unable to contain macros. Current PowerPoint opens both but saves PPTX.

How do I open a PPTX file without PowerPoint?

Use PowerPoint for the web (free with a Microsoft account), Google Slides, Keynote on Apple devices, or LibreOffice Impress.

How do I convert PPTX to PDF?

In PowerPoint, choose File, Export or Save As, and pick PDF. Keynote, Google Slides and LibreOffice export PDF too, and soffice --headless --convert-to pdf deck.pptx does it on a server.

Why do my fonts change when I open the deck elsewhere?

Fonts aren't embedded by default, so the other computer substitutes its own. Embed the fonts when saving, stick to common fonts, or present from a PDF.

Why won't the video in my presentation play?

It may be linked rather than embedded, so the video file didn't travel with the deck, or the device can't decode its format. Embed the video as an MP4 with H.264 video and AAC audio.

Is a PPTX file a ZIP file?

Yes. Rename a copy to .zip and open it: slides are in ppt/slides/, and pictures and videos in ppt/media/.

Can a PPTX file contain a virus?

It can't contain macros, but it can hold links, actions that start programs, and embedded objects. Keep Office updated and be wary of unexpected presentations that ask you to click something.

Related formats

Other file types explained

PPT filePDF fileAll file types

Keep going

Related

Host a PPTX file

Put a PowerPoint deck online at its own address.

Share a PPTX file

Send a presentation as a link instead of an attachment.

Host a presentation

Publish slides people can open from a link.

Sources

Last reviewed 27 October 2026.