How to compress a video on Mac without losing quality
First, what “without losing quality” can mean
Truly lossless video compression exists, but it barely makes files smaller — useless for email or chat. What you can get is visually lossless compression. iPhone videos and screen recordings are recorded at high bitrates, so re-encoding them at a sensible bitrate often makes them several times smaller with no difference you’d notice.
Quality only suffers visibly when you force a long video into a small limit. Then the trick is to lose quality gracefully: lower the resolution before the picture turns into blocks.
Free options already on your Mac
1. QuickTime Player
- Open the video in QuickTime Player.
- Choose File → Export As → 1080p, 720p or 480p.
- For 1080p and 4K, choose “Greater Compatibility (H.264)” if the recipient may be on Windows or Android, or “Smaller File Size (HEVC)” for Apple devices.
Free, no watermark, keeps audio. You can’t set a target size, so you may need a couple of tries.
2. Finder: Encode Selected Video Files
Select one or more videos in Finder, right-click → Services (or Quick Actions) → Encode Selected Video Files, then pick a setting such as 1080p or 720p. It’s handy for batches; again, there’s no size target.
3. iMovie
File → Share → File lets you choose a resolution and a quality level, and shows an estimated size before exporting. Good if you also need to trim.
Free and more precise: HandBrake
HandBrake is free and open source with excellent quality. It doesn’t take a target size directly; instead you choose an average bitrate:
video kbps ≈ (target MB × 8000 ÷ seconds) − audio kbps
For example, 50 MB for a 4-minute (240 s) video gives about 1,670 kbps in total; minus 128 kbps of audio leaves ~1,540 kbps for video. Enable 2-pass encoding for more accurate sizes and keep a ~5% margin. The interface is technical, but the results are reliable.
Tips that keep quality high
- Resolution before bitrate. If the math gives less than ~1,000 kbps, 720p will look better than 1080p.
- Frame rate. Talking heads and screen recordings look the same at 30 fps; going from 60 to 30 fps saves a lot.
- H.264 vs HEVC. HEVC is about a third smaller at the same quality, but H.264 plays everywhere. Choose H.264 when you don’t know what the recipient uses.
- Don’t compress twice. Always start from the original, not from an already-compressed copy.
- Keep the audio. AAC at 128 kbps is a tiny fraction of the file and sounds clean. “Compress video without losing audio quality” mostly means: make sure your tool doesn’t drop or mangle the audio track.
Always check the result
Compressor apps occasionally produce files that look fine in Finder but don’t work: no sound, a video that stops halfway, or a format the recipient can’t open. Before sending, play the compressed file to the end with the sound on, and confirm its size in Finder.
Where SizeFit fits in
SizeFit does the bitrate math for you: pick a target (Gmail, Discord, an upload form, or any MB value with Pro), and it encodes with Apple’s hardware encoder, re-encodes automatically if the result is over, and then decodes the entire output to check the size, duration, audio presence and loudness, and that every frame decodes. Your original is opened read-only. The free version has no watermark and no file limit.
Compress to an exact size — and prove it still works
SizeFit is coming soon to the App Store for Mac, iPhone and iPad.