Compress PPTX online — reduce PowerPoint file size
Make a presentation smaller without changing the slides.
A phone photograph dropped onto a slide keeps its full resolution and stays that way, which is how a twelve-slide lesson becomes forty megabytes and stops fitting in an email. This re-encodes the pictures and leaves everything else exactly where it was.
Why PowerPoint files get so big
Almost always the pictures. A photo inserted into a slide often keeps every pixel the camera took — 4000 across or more — even when it fills one corner of the slide.
What the compression does — and what it leaves alone
Pictures are re-encoded as JPEG, and anything wider than the setting is scaled down: 1280 pixels across for Strong, 1600 for Balanced, 2200 for Light. Small PNGs — screenshots, diagrams, logos — and PNGs with a transparent background stay PNG, so text stays sharp and nothing gains a white box. GIFs are left alone, because a JPEG would keep only the first frame of an animation. A picture is replaced only when the new one is smaller.
Nothing else changes: text, positions, animations, transitions, speaker notes and slide order stay exactly as they were. Video and sound inside slides are not compressed, and charts and EMF or WMF drawings are left alone — so a deck that is heavy because of a video stays heavy. An old .ppt file has to be saved as .pptx first.
Reduce PowerPoint file size for email
Most email services refuse attachments over 20 to 25 MB. A test deck of 12 slides, each a full-screen 4K desktop wallpaper of about 1 MB, weighed 13.6 MB; Balanced brought it to 0.98 MB and Strong to 0.57 MB, with every slide unchanged. Detailed photographs shrink less than those smooth images did.
Compress PowerPoint without losing quality
Light keeps pictures up to 2200 pixels across at high quality — more than a 1080p projector or most laptop screens can show of a full-slide picture — and still took the test deck from 13.6 MB to 2.4 MB. Text, charts and shapes lose nothing at any setting, because they are not pictures.
How to shrink a PPTX on Mac, Windows or Chromebook
The same way on all three: open this page, drop the .pptx, pick a setting and download. Nothing is installed and the file never leaves the browser, so it also works on a school Chromebook or a work laptop where you cannot install software.
How to use it
- Add the .pptx file.
- Pick how hard to compress.
- Download the smaller file.
Why use this tool
Completely private
Everything runs inside your browser. Your files and text are never sent to a server.
Free, with no limits
No sign-up, no watermarks and no cap on how many times you can use it.
Instant results
There is no upload or queue to wait for, so results appear as fast as your device can work.
Works on any device
Runs in any modern browser on phone, tablet or desktop. Nothing to install.
Frequently asked questions
- Does it change my slides?
- No. Text, positions, order, animations and speaker notes are untouched. Only the pictures stored inside the file are re-encoded.
- Will the pictures look worse?
- A little, which is what compression is. On a projector the difference is usually invisible. Balanced is a safe default and Light barely touches quality.
- Why did nothing change?
- Either the deck is heavy for some other reason, or its pictures are already small. A picture is only replaced when the new version is genuinely smaller, so no picture ever gets bigger.
- What about diagrams and charts?
- Drawings stored as vectors are left alone, because turning one into a bitmap makes it blurry rather than smaller. Small PNG screenshots keep their format too, since a screenshot turned into a JPEG gains a halo around every letter.
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