Compress PowerPoint decks in your browser
Slides are light; full-resolution photography is not. We re-encode JPEG and PNG pictures inside the deck and rebuild its package. Text, masters, notes, transitions and animation stay where they are.
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No PPTX to hand?
How to compress a PowerPoint presentation
The deck is read in this browser tab. It is never uploaded, copied to a server or added to a presentation library.
72% at 1600px is ample for a projector and a video call. Keep 2400px when people need to zoom into photographs.
It reports the number and weight of pictures it found and says when vector drawings or already efficient images were left alone.
The output is a normal .pptx for PowerPoint, Keynote, LibreOffice Impress or Google Slides, with the same slide order and notes.
Why a .pptx is mostly pictures
A .pptx is a ZIP container. Slides, themes, speaker notes, transitions and animations are XML parts, while every pasted JPEG and PNG lives separately in ppt/media. Rename a copy to .zip and the deck opens into that package of files.
PowerPoint keeps the source pixels even when a picture covers only a quarter of a slide. A dozen 12 megapixel photographs can turn ten lightweight slides into a 70MB attachment, although a projector or video call displays only a fraction of their detail.
This tool re-encodes those raster pictures in their existing formats and under their existing package names. It never lays a slide out again, so text boxes, fonts, masters, cropping, links, notes, comments, transitions and animation timing are not nudged.
Photo decks tend to shrink harder than any other office file. A deck made from vector diagrams and text may barely change, because XML is already deflated and EMF or WMF artwork cannot safely be rasterised behind your back. The result tells those two cases apart.
PowerPoint compression FAQ
Why is my PowerPoint presentation so large?
Almost always because PowerPoint retained the original pixels from every pasted photograph and screenshot. Making a photo smaller on the slide changes its display box, not the media stored in the package. Video and audio can also dominate a deck, but this picture compressor deliberately does not transcode those streams.
Will compression move text or break animations?
No. Slide XML, masters, layouts, text boxes, speaker notes, transitions, animation timing, hyperlinks and relationships are copied through. A JPEG remains a JPEG and a PNG remains a PNG under exactly the same entry name, so PowerPoint still finds it at the same crop, size and position.
How small should pictures in a presentation be?
For a 1920 by 1080 projector, a 1600 pixel longest edge is already enough for most pictures because few occupy the whole slide. Use 2400 when the deck will be shown on a 4K screen or handed out for people to inspect closely. Quality around 72% removes camera noise and invisible detail without making normal viewing look soft.
What happens to EMF and WMF diagrams?
They stay byte for byte. EMF and WMF are vector drawing formats commonly produced by pasted Office charts, and converting them to pixels would make lines softer and could change how the slide prints. Native PowerPoint shapes and charts also remain in their XML parts. The tool reports recognised vectors rather than claiming it compressed them.
What does “squeeze screenshots harder” do?
It cuts each PNG picture to at most 256 colours before re-encoding it. User-interface captures, diagrams and other flat artwork usually need fewer colours and shrink sharply. Photographs saved as PNG can reveal banding in smooth gradients after palette reduction, so use the switch for screenshot-heavy decks rather than every presentation.
Can it open an old .ppt or an encrypted .pptx?
No. An old .ppt is a binary presentation, not an OOXML ZIP package; open it in PowerPoint or LibreOffice and save a .pptx copy first. A password-protected or encrypted PPTX cannot be inspected safely without decryption and is refused rather than partly rewritten.
Does it compress video or audio embedded in the deck?
No. Re-encoding media streams would change codecs, playback compatibility and timing, which is a much broader job than rebuilding a presentation package. The tool confines itself to JPEG and PNG pictures. If video is the weight, use PowerPoint’s own Compress Media command where it can test playback inside the deck.
Is a confidential presentation uploaded?
No. The archive is read, its pictures are re-encoded and the result is written entirely in this tab. There is no upload endpoint and no server-side copy of your slides or speaker notes.
Related
Same format joins the queue. Anything else re-routes to its own tool.