Compress Video on a Mac
Runs in Safari or Chrome on your Mac. No install, no upload.
When you load a video, the After size is filled in with a size computed from its resolution and frame rate. Tap 70%, 50%, 30% or 10%, or click the After size and type an exact number in MB. The video is compressed by your Mac's video encoder and never leaves the Mac.
Free Video Compressor
No sign-up. No upload. No size limit.
Nothing is uploaded — the file is compressed on your device.
What macOS has built in
QuickTime Player's File > Export As offers 4K, 1080p, 720p and 480p. At 4K and 1080p you also choose Smaller File Size (HEVC) or Greater Compatibility (H.264) (QuickTime Player User Guide, checked September 2026). Photos exports video at 480p, 720p, 1080p or 4K. The Finder's Encode Selected Video Files changes the resolution and lets you pick higher quality or wider compatibility. None of these has a field for a file size.
iMovie comes closer: its Custom quality setting has a bit rate slider and shows the estimated file size (iMovie User Guide). HandBrake is free and open source, with many more controls. Here you type the size itself: 25 MB for a Gmail attachment (Gmail Help) or 20 MB for a free Discord account (Discord patch notes), both checked September 2026. The Discord page opens at 20 MB.
Compressing in the browser on a Mac
Drag the file onto the page. Screen size lists Original and each lower step. Advanced has Frame rate, Format and Audio. Format lists only what this browser can encode on your Mac, so Safari and Chrome may show different choices; MP4 (H.264) is the default.
On some Macs, Chrome stops decoding certain H.264 files partway through. The page then restarts with software decoding, replaces any frame that still can't be decoded with the previous one, and states in the result how many frames were replaced.
Audio with more than two channels (5.1 and up) is mixed down to stereo when it is re-encoded. If the clip needs cutting first, use Trim Video ↗.
Privacy and large files
The video never leaves the Mac, and once the page has loaded it works with no network. Files of several GB work because the output is written to disk as it is produced. If you close the tab before downloading, the last result stays in the browser for up to 7 days.
Frequently asked questions
Does this work in Safari?
Yes. Chrome and Edge work too. The Format menu can differ between them, because each lists only what it can encode on your Mac.
Why can't QuickTime export to a set size?
Export As offers resolutions only, plus HEVC or H.264 at 4K and 1080p.
Chrome says some frames were replaced. What happened?
Chrome stopped decoding the file partway, so the page switched to software decoding and filled frames it still couldn't decode with the previous frame. You can also try the same file in Safari.
Is the video uploaded anywhere?
No.
Compress Video on a Mac
Opens the compressor with a target size computed for this page.