Where the size of a PPTX file comes from
What the compressor changes
Choosing a compression level
When you may not save much
Features explained
Three compression levels
You choose between Recommended, Extreme and Low. Each sets the JPEG quality and the largest image size, so you can trade file size against sharpness. The level applies to every image in the file; there is no per-image control.
Downscaling of oversized images
Pictures whose longest side is above the level's limit are reduced in size while keeping their proportions. Photos taken on modern phones are often far larger than a slide needs, so this is where most of the saving comes from. Detail beyond the limit cannot be recovered afterwards.
Replaced only when smaller
If recompressing an image does not make it smaller, the original is kept. The same applies to images that cannot be read by the browser. This prevents a file from getting larger because of one image.
Small images are skipped
Images of 100 KB or less are not touched, since recompressing them saves little and can only lower their quality.
Progress with image count
While working, the tool shows a percentage and a status line such as "Compressing image 3 of 12...". The status text is shown in English.
Before and after size
When the job is done, the page shows how many percent were saved and the size in MB before and after. If nothing could be reduced, it shows 0%.
Original file stays unchanged
The tool makes a new file for download, named after your file with "compressed_" in front. Your original presentation is not modified.
What can you use it for?
Email attachments
Make a photo-heavy presentation small enough to attach to an email without sending a download link.
Upload forms and learning portals
Get under a file-size limit set by a website, school portal or application form.
Sharing through messaging apps
Send a smaller file over a slow or limited mobile connection.
Saving storage
Shrink older decks you want to keep, while holding on to the original file if full quality matters.
Tool information
| Tool type | PowerPoint file size reducer |
|---|---|
| Input | PowerPoint .pptx file |
| Output | Compressed .pptx file named compressed_<original name> |
| Maximum file size | 100 MB |
| Images processed | JPG, JPEG and PNG files larger than 100 KB |
| Output image format | JPEG |
| Recommended level | 70% JPEG quality, longest side up to 1920 px |
| Extreme level | 40% JPEG quality, longest side up to 1280 px |
| Low level | 85% JPEG quality, longest side up to 2560 px |
| Not compressed | Videos, audio, GIF, SVG and other non-JPG/PNG files |
| Text, shapes, animations, layout | Not changed |
| Multiple files at once | No, one file at a time |
| Password-protected files | Not supported |
| Processing | In your browser |
| Sign-up | None |
| Result display | Percent saved and size before and after |
Benefits
- Often the quickest way to make a photo-heavy deck small enough to send.
- Three levels let you choose between smaller size and sharper images.
- Your original file is not modified.
- The file is processed in your browser, not sent to our server.
Limitations
- Compression is lossy. Images are re-saved as JPEG, so quality goes down, and the lower the level the more visible it is. The lost detail cannot be restored.
- PNG images are also converted to JPEG, and JPEG does not support transparency. Transparent areas, such as the background of a logo, can turn black or solid. Check slides that use transparent images.
- Screenshots and images with small text or sharp edges can show visible blur or artifacts at the Extreme level.
- Large images are scaled down to the level's limit even if they are shown small on the slide, so a slide that zooms into a picture may look softer.
- Only JPG, JPEG and PNG images are processed. Videos, audio, GIFs and vector graphics are left alone, so decks made large by those will not shrink much.
- The saving depends on the images in your file. A deck with few or small images may shrink very little, and the result can be about the same size as the original.
- The whole file is loaded into your browser's memory, so very large presentations can be slow, especially on phones or older computers.
- Password-protected or damaged files cannot be opened. Only one file can be compressed at a time.
Privacy and file handling
Your presentation is opened and repackaged by your browser. The images are decoded and re-encoded on your device, and the compressed file is created locally for you to download. The compression does not send the presentation to our server.
Tips
- Start with Recommended. Try Extreme only if the file is still too large, and use Low for decks where image sharpness matters.
- Open the compressed file and look through the slides before you send it, particularly slides with logos or screenshots.
- Keep the original file. The compressed version cannot be turned back into the full-quality original.
- If your deck is large because of video, compress or trim the video in a video tool first.
- Remove unused slides and unnecessarily large pictures in PowerPoint before compressing for an even smaller file.
Frequently asked questions
Will compressing change my slide text or animations?
No. The tool changes only JPG, JPEG and PNG images. Text, shapes, animations and layout are left as they are.
Will my images lose quality?
Yes. Images over 100 KB are re-saved as JPEG at a lower quality, and large ones are also scaled down. The Low level keeps the most detail and Extreme keeps the least.
Why do transparent logos look wrong after compression?
PNG images are converted to JPEG, and JPEG cannot store transparency, so transparent areas can become black or solid. If your slides rely on transparent images, check them after compressing.
How much smaller will my file be?
It depends on how many large images the deck contains. A deck full of big photos can shrink a lot, while a mostly-text deck may barely change. The page shows the exact result after compression.
Why did my file get no smaller, or hardly smaller?
Your file may have few images, images already under 100 KB, or its size may come from video or audio, which this tool does not compress. An image is only replaced when the new version is smaller, so some files see almost no change.
Does it compress videos inside the presentation?
No. Only JPG, JPEG and PNG images are processed. Videos, audio, GIFs and vector images are left unchanged.
Is my presentation uploaded to a server?
No. The file is processed in your browser, and the compressed file is created on your device.
Is my original file changed?
No. You download a new file named compressed_ followed by your original file name, and the original stays as it was.
What are the file limits?
One .pptx file at a time, up to 100 MB. Password-protected or damaged files cannot be compressed and will show an error.