SlimKey
Compress your Keynote presentations instantly.
Drop your .key file here
or click to browse
Three simple steps.
Compress any Keynote file in seconds.
Upload
Drag and drop your Keynote presentation or click to select it. SlimKey accepts any .key file.
Adjust
Use the quality slider to find your perfect balance between file size and image clarity.
Download
Get your optimized Keynote with a detailed compression report. Your original stays untouched.
Why SlimKey?
Designed to make your Keynote workflow effortless.
Up to 70% smaller files
Intelligent image conversion to optimized JPEG delivers dramatic file size reductions without visible quality loss.
Transparency preserved
PNG and TIFF images with alpha channels are kept in their original format. Only opaque images are converted.
Pixel-perfect output
All internal references are updated, including Apple's proprietary IWA format. Your slides look exactly the same.
Built for email
Compressed files fit easily within attachment limits. No more “file too large” errors when sharing presentations.
Faster cloud sync
Smaller files sync faster across iCloud, Google Drive, and Dropbox. Save time and bandwidth every day.
Reclaim storage
Large presentations consume valuable disk space. Compress them to free up room on your Mac or iPad.
Two ways to reduce
Keynote file size.
Whether you prefer working inside the app or from your browser, there’s an option for you.
Option 1: Using Keynote on Mac
Built-in feature · Requires macOS
Apple Keynote includes a built-in tool to reduce file size directly from the app. If your presentation contains high-resolution images, audio clips, or video, this method can help you trim unnecessary data before sharing.
How to do it
- 1Open your presentation in Keynote on your Mac.
- 2Go to File → Reduce File Size from the menu bar.
- 3Choose which adjustments to apply:
Scale down large images
Images are resized to match their actual display size in the presentation. Unused pixel data is removed, preserving visual quality on screen.
Remove trimmed media
If you’ve trimmed audio or video clips, the unused portions are permanently deleted from the file.
Video format options
Choose Most Compatible (H.264) for broad device support, or High Efficiency (HEVC) for better quality at smaller sizes on newer Apple devices (requires macOS 10.13+ and compatible hardware).
Video quality
Sets the maximum resolution for movies in the file. Videos already below this resolution are not upscaled.
- 4Click Reduce This File to apply changes to the original, or Reduce a Copy to keep the original untouched and save an optimized version separately.
Note: This method requires Keynote on a Mac. It works well for trimming media and downscaling images, but the image compression is limited — it resizes rather than re-encodes. For deeper image optimization, consider the online option below.
Option 2: Using SlimKey
Online · Free · No installation
SlimKey takes a fundamentally different approach. Instead of just resizing images, it re-encodes every image inside the Keynote package to optimized JPEG at your chosen quality level — while carefully updating Apple’s internal binary references so your presentation opens perfectly.
What makes it different
Deep image re-encoding
Converts PNG, TIFF, and HEIC images to optimized JPEG. Apple’s method only removes unused pixels — SlimKey actually compresses the image data.
Adjustable quality control
A slider from 1 to 100 gives you precise control over the compression level. Apple’s tool doesn’t offer this granularity for images.
Smart transparency handling
Images with alpha channels (transparency) are automatically preserved in their original format, since JPEG doesn’t support transparency.
Works from any browser
No Mac required. Compress Keynote files from Windows, Linux, ChromeOS, or even your phone.
Non-destructive by default
SlimKey always creates a new compressed copy. Your original file is never modified.
At a glance
| Feature | Keynote (Mac) | SlimKey |
|---|---|---|
| Image re-encoding | No | Yes |
| Quality slider | No | 1–100 |
| Trim audio/video | Yes | No |
| Video conversion | H.264 / HEVC | No |
| Transparency preserved | Yes | Yes |
| Works on any device | Mac only | Any browser |
| Typical reduction | 10–30% | 30–70% |
| Requires installation | Yes | No |
Both methods are complementary. For presentations heavy on video and audio, start with Keynote’s built-in tool. For maximum image compression, use SlimKey — or use both for the best results.
Frequently Asked Questions
Is SlimKey free to use?
Yes, SlimKey is completely free. No account, no signup, no hidden fees. Just upload your file and compress it.
Will my presentation lose quality?
SlimKey uses smart compression. You control the JPEG quality (1–100), and images with transparency are preserved in their original format. At the default quality of 70, the difference is virtually imperceptible on screen.
Is my file safe?
Your file is processed on our server and automatically deleted after you download the compressed version. We do not store, share, or access your presentations.
What file formats does it support?
SlimKey works with Apple Keynote files (.key). It processes internal JPEG, PNG, TIFF, and HEIC images within the presentation package.
Does it work with Keynote on iPad and iPhone?
Yes! The compressed .key file is fully compatible with Keynote on macOS, iPadOS, and iOS. Simply download and open it.
How much can I reduce my file size?
Typical reductions range from 30% to 70%, depending on the number and type of images in your presentation. Files with many high-resolution photos see the biggest improvements.
SlimKey is the easiest way to compress Apple Keynote presentations online. Reduce file size by up to 70% by converting images to optimized JPEG while preserving quality and transparency. Free, private, and no signup required.