Compress Presentations to Reduce File Size
Optimize presentations with quality presets, DPI control, and image compression
Drop your presentations here
or click to browse files
How much a presentation actually shrinks
We ran the same compression this page runs in your browser over two real decks and measured every preset. Almost all of the saving comes from re-encoding the photographs inside the file, so how much you gain depends on how image-heavy your deck is.
Tested on two decks: a photo-heavy one at 5169 KB (a full-screen 1920x1080 photo on all 10 slides) and a mostly-text one at 53.9 KB (11 slides, 2 photos). Both saved by LibreOffice.
| Preset | JPEG quality | Photo deck | Saved | Text deck | How it looks | Best for |
|---|---|---|---|---|---|---|
| Fast | 30 | 730.9 KB | 85.9% | 12.3% | Visible softening on photos | Email attachments and size limits |
| Normal | 50 | 943.4 KB | 81.7% | 11.5% | Slight softening, fine on screen | The sensible default |
| Maximum | 70 | 1393.4 KB | 73% | 9.4% | Hard to tell from the original | Client-facing decks |
| Ultra | 85 | 2272.3 KB | 56% | 2.4% | Effectively identical | When quality matters more than size |
- On the photo-heavy deck the savings are large: 85.9% at Fast and 81.7% at Normal, taking 5169 KB down to 943.4 KB. If your deck is full of photographs, this tool will help a lot.
- On the mostly-text deck there is far less to gain, 12.3% at best. Slide text and layout are already tiny once zipped, so there is very little slack to recover.
- Repacking the file without touching the images saved 6% on the photo deck and nothing at all on the text deck. That confirms the images are what matters, not the ZIP settings.
- Higher presets keep more detail and save less: Ultra gave back 56% against Fast's 85.9%. Pick Normal unless you have a reason not to.
What compression does not change
Your text, layout, tables, shapes, transitions and any macros are all preserved exactly. Only the photographs inside the file are re-encoded, and they keep their original pixel dimensions, so nothing is resized or cropped.
Measured on two representative decks. Your own results depend on how many photographs your slides contain and what quality they were saved at. Pictures already saved small will barely change.
Supported Presentation Formats
Compress all major presentation and slideshow formats
PowerPoint Formats
PowerPoint's XML-based deck, 2007 onward.
Photos inside are re-encoded at the quality you pick.
Where most of the saving comes from on image-heavy decks.
A PowerPoint deck that carries VBA macros.
Handled like PPTX, with the macro project preserved.
Compression never touches your VBA code.
PowerPoint's legacy binary deck (97-2003).
Sent to our server, since browsers cannot unpack it.
Convert it to PPTX first for the best results.
Slideshow Formats
A PPTX that opens straight into the slideshow.
Images are re-encoded in your browser, same as PPTX.
Playback behaviour is unchanged.
A macro-enabled slideshow file.
Compressed in your browser with macros kept intact.
Same engine as PPSX.
The legacy slideshow format (97-2003).
Sent to our server for processing.
PPSX compresses better and stays in your browser.
Template Formats
The modern PowerPoint template format.
Images in the template are re-encoded in your browser.
Styles and layouts survive untouched.
A PowerPoint template that also carries macros.
Compressed in your browser, macros preserved.
Same handling as POTX.
The legacy PowerPoint template format (97-2003).
Sent to our server, since it is a binary format.
POTX is the modern equivalent.
Open Source Formats
The OpenDocument presentation format.
Unpacked and re-compressed in your browser.
Impress files are handled the same way as PPTX.
Export Formats
Image files exported from a presentation.
Each picture is re-encoded at your chosen quality.
Use the image compressor for standalone photos.
References
- ECMA-376: Office Open XML File Formats - Ecma International
- [MS-PPTX]: PowerPoint (.pptx) Extensions to the Office Open XML File Format - Microsoft Learn
- OpenDocument Format for Office Applications v1.3 - OASIS
- RFC 1951: DEFLATE Compressed Data Format Specification version 1.3 - RFC Editor
- APPNOTE.TXT: .ZIP File Format Specification - PKWARE
- HTMLCanvasElement.toBlob() - MDN Web Docs, Mozilla
- Portable Network Graphics (PNG) Specification - W3C
- JSZip documentation