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How to Compress a Video on Mac: Cut the File Size With QuickTime or a Video Compressor

Compress Videos With QuickTime Player on Mac

When a clip is too large to email, you can use QuickTime to compress your video without installing anything. Export it at a lower resolution like 720p, and you get a lighter copy. That copy is a .mov, because QuickTime Player doesn't export MP4.

Here's how to compress video in QuickTime Player:

  1. Open the video in QuickTime Player.
  2. Choose File > Export As, then select 4K, 1080p, 720p or 480p. Resolutions larger than your video are dimmed.
  3. For 4K or 1080p, click the Format menu and choose Smaller File Size (HEVC) or Greater Compatibility (H.264).
  4. Name the copy, pick where to save it, and click Save.

Export As saves a copy, so the original stays on your hard drive. Compare the two in Finder before you send anything.

Pick a Resolution and Codec for a Smaller File Size

In QuickTime, you reduce the file size with two choices: a lower resolution and, at 1080p or 4K, a lighter codec. Fewer pixels per frame leave less data to store.

Here is what the 1080p, 720p and 480p options export, according to Apple's QuickTime Player User Guide:

  • 1080p: H.264 or HEVC, up to 1920 × 1080.
  • 720p: H.264, up to 1280 × 720.
  • 480p: H.264, up to 640 × 480.

A codec is the method that packs the images into data. The container is the box that holds the result, here a .mov.

HEVC (H.265) is the codec behind Smaller File Size, and H.264 is the one behind Greater Compatibility. If you don't know whether the person you send it to can play HEVC, choose Greater Compatibility.

Apple also notes that the exact resolution and data rate depend on the original, so video file sizes after export vary from clip to clip. For a clip you want to email, start at 720p, and drop to 480p if it still won't attach.

Set a Target Bit Rate in iMovie

If iMovie is on your Mac, it gives you a finer setting than QuickTime's fixed resolutions. Import the video into iMovie if needed, select it in the browser, then choose File > Share > File. In the Quality menu, select Custom, then drag the slider to set a target bit rate (the amount of data used per second of video).

As you drag, you'll see the estimated file size update under the preview thumbnail. That number is an estimate, not the final size, so check the export before you send it.

Use this route when you want to compress a clip toward a size rather than a resolution.

How to Compress a Video to MP4 on Mac in Your Browser

QuickTime chooses the size for you, and iMovie only estimates it. When you need an MP4 under a set limit, use a free video compressor for Mac that runs in the browser. There's no App Store download.

Vidmini runs in recent versions of Safari, Chrome, Edge and Firefox. You choose a target size, with presets of 8, 10, 25, 50 or 100 MB, or a quality level: high, balanced or smallest.

You can also cap the resolution at 1080p, 720p or 480p. The output is H.264 video with AAC audio (a common audio codec) in an MP4.

Many other online compressors upload your video to a server, and some add a watermark or cap the upload size. Vidmini reads and processes the video on your Mac. Nothing is uploaded, there's no account, no watermark, and no size limit set by Vidmini.

For an iPhone clip, compress a MOV on your Mac without installing anything. For an MP4 or WebM, compress the video to a target size in your browser.

What Video Compression Costs, and What to Try First

Each way to compress video on Mac shown above re-encodes the file. During video compression, the encoder rebuilds each frame with less data, and some detail goes.

So can you compress video without losing quality? Not strictly: every re-encode discards some data, though at a light setting the difference can be hard to see. Copying the streams into a new container keeps every frame intact, but it doesn't reduce the size.

You can still control how much you lose. Start with a light setting, check the result, and go further only if it's still too much for the limit.

Trimming the start and end first removes seconds you would otherwise pay for.

Two limits apply to Vidmini. HDR video (a wider range of brightness and color) from a recent iPhone can look slightly washed out after re-encoding. Vidmini also handles one file at a time, so a folder of clips means one export after another.

If you'd rather install an app, many Mac guides point to HandBrake, which is free.