Does compressing a video reduce its quality?

Yes, compressing a video usually reduces quality a little, because the file keeps less data. The loss is often hard to see on a phone screen, especially at 720p or 1080p. Choosing HEVC instead of H.264 helps, since Apple's QuickTime Player User Guide lists HEVC as the Smaller File Size option.

What is the difference between HEVC and H.264?

HEVC and H.264 are video codecs, which are the methods used to squeeze video data. HEVC, also called H.265, makes smaller files at similar quality. H.264 is older and plays on more devices. QuickTime Player labels HEVC as Smaller File Size and H.264 as Greater Compatibility when exporting 4K or 1080p video.

How do I send a large video from a Mac?

A large video can be sent from a Mac with Mail Drop, which handles attachments up to 5 GB (5,120 MB) per message. Apple's Mail Drop limits page says each attachment expires after 30 days. For normal email, compressing the video to under about 10 MB is the safer choice.

Can I compress a video without lowering the resolution?

Yes, a video can be compressed without lowering the resolution. In QuickTime Player, export at the same 1080p or 4K preset and choose Smaller File Size (HEVC). In iMovie, keep the resolution and lower the bit rate with the Custom quality slider, which shows the estimated file size as it moves.

Is it safe to compress videos online?

Online video compressors work, but every file must be uploaded to another company's server first. A 1 GB (1,024 MB) video can also take a long time to upload on a slow connection. For private or work videos, the built-in Mac tools are safer because the file never leaves the computer.

How to Compress a Video on Mac (4 Ways)

Video & audio

Quick answer

How do I compress a video on Mac?

To compress a video on a Mac, open it in QuickTime Player, choose File → Export As, and pick a smaller preset such as 720p or 480p. A lower resolution makes a smaller file. For 4K or 1080p, Apple's Smaller File Size option uses HEVC. iMovie and Finder's Encode Selected Video Files can also shrink videos.

Quickest built-in way: QuickTime Player → File → Export As → 720p or 480p.
Keep full resolution and still save space by choosing HEVC (Smaller File Size) at 4K or 1080p.
iMovie lets you set a custom bit rate and shows the estimated size as you drag the slider.
For many videos at once, a right-click tool like FinderBuddy's Compress Video saves the most time.

You try to email a two-minute video and Mail says it's too big. Or a chat app sits on the upload bar forever. Phone and screen videos get large fast, and it's easy to end up with a file over 1 GB (1,024 MB).

This is simpler than it sounds. Your Mac already has three free ways to make a video smaller, and none of them upload your file anywhere.

Video compression just means saving the video again with less data. You can lower the resolution (fewer pixels), lower the bit rate (less data per second), or use a more efficient codec like HEVC. Every method below uses one or more of those three levers.

How do I compress a video on Mac with QuickTime Player?

QuickTime Player shrinks a video by exporting it at a lower resolution. This is the fastest built-in fix, and the steps below follow Apple's QuickTime Player User Guide.

Open the video in QuickTime Player.
Choose File → Export As.
Pick 720p or 480p for a much smaller file. Presets larger than your video are dimmed.
If you pick 4K or 1080p, open the Format menu and choose Smaller File Size (HEVC).
Name the file, choose a folder, and click Save.

Here's the trade-off. HEVC files are smaller, but Apple labels H.264 as the Greater Compatibility choice. If the video is going to someone on an older PC, H.264 is the safer pick. You can check on the export with Window → Show Export Progress.

One catch: QuickTime always saves a MOV file. If the site you're uploading to wants MP4, read our guide to converting MOV to MP4 on Mac.

How do I reduce video file size on Mac from Finder?

Finder can shrink several videos at once with Encode Selected Video Files. Apple's QuickTime automation tips say it lets you change the resolution and choose between higher quality and wider device support.

Select the videos in Finder.
Control-click (or right-click) and choose Encode Selected Video Files. On some macOS versions it sits inside the Services or Quick Actions submenu.
Pick a lower resolution than the original.
Choose quality or compatibility, then click Continue.

This part is actually really easy, and it's the best free option for a batch. You get fewer choices than iMovie, but you never open an app.

How do I compress a video in iMovie?

iMovie gives you the most control. You export with File → Share → File, then lower the resolution or set a custom bit rate while iMovie shows the estimated file size.

Add the video to an iMovie project and select it.
Choose File → Share → File.
Open the Resolution menu and pick something lower, like 720p.
Open the Quality menu and choose Custom. Drag the slider until the estimated size fits your limit.
Click Next, then Save.

According to Apple's iMovie export guide, the Custom slider sets a target bit rate. The Compress menu is different. Apple's iMovie sharing article says it adjusts how long the conversion takes, so don't expect it to change the size much.

The faster way: compress videos with a right-click

FinderBuddy adds a video compressor, Compress Video, to Finder's right-click menu. You pick Smaller File, Balanced, or High Quality, and it shows the estimated size before you start.

Select one video, or a whole batch, in Finder.
Right-click and choose FinderBuddy → Compress Video.
Pick a preset, check the estimated size, and start.

It saves as H.264 or HEVC and keeps rotation, dates, location, and HDR. In FinderBuddy's own 2.0 release demo, a 4K clip went from 73.1 MB to 9.3 MB. Your results will depend on the video. Originals are kept, and nothing leaves your Mac.

FinderBuddy is a free download with a set of free tools, and the video tools unlock with a one-time license. Get it from the download page, then follow the setup guide.

How small does your video need to be?

Aim for the limit of wherever the video is going. For email, Apple's iMovie sharing article says the recommended limit is usually 10 MB. For bigger files, Mail Drop can carry much more.

Where it's going	Size to aim for
Regular email attachment	Under about 10 MB (Apple's iMovie advice)
Mail Drop from Apple Mail	Up to 5 GB (5,120 MB) per message
Chat apps and upload forms	Check the app's own limit

Apple's Mail Drop limits page explains that attachments expire after 30 days. That's fine for sharing, but not for long-term storage.

A quick size formula

File size is roughly bit rate times length. So if a 1-minute video must fit under 10 MB, you need about 1.3 Mbps (megabits per second) for video and sound together. Longer videos need a lower bit rate to fit the same limit. That's why a 10-minute clip rarely fits in an email.

What this means for you

One video, quick fix: QuickTime Player at 720p.
Need it sharp on a big screen: keep 1080p or 4K and choose HEVC.
Hitting an exact size: iMovie's Custom quality slider.
A folder of videos: Finder's Encode Selected Video Files, or FinderBuddy if you want presets and a size preview.
Only need the audio: save it as MP3 and the file gets far smaller.

Sending photos too? Our guide to reducing photo size for email covers the same problem for pictures.

My take

I'd start with QuickTime at 720p. For most videos sent to friends or coworkers, 720p looks fine on a phone and the file drops a lot.

I'd only reach for iMovie when I have a hard size limit to hit. And if compressing videos is a regular part of your week, a right-click tool with a size preview takes the guesswork out.

The bottom line

You've got this. Learning how to compress a video on Mac comes down to one choice: fewer pixels, less data per second, or a smarter codec. QuickTime, Finder, and iMovie cover all three for free, and none of them upload your video.

Pick the method that fits the job, check the new size, and send it off.

Frequently asked questions

Does compressing a video reduce its quality?: Yes, compressing a video usually reduces quality a little, because the file keeps less data. The loss is often hard to see on a phone screen, especially at 720p or 1080p. Choosing HEVC instead of H.264 helps, since Apple's QuickTime Player User Guide lists HEVC as the Smaller File Size option.
What is the difference between HEVC and H.264?: HEVC and H.264 are video codecs, which are the methods used to squeeze video data. HEVC, also called H.265, makes smaller files at similar quality. H.264 is older and plays on more devices. QuickTime Player labels HEVC as Smaller File Size and H.264 as Greater Compatibility when exporting 4K or 1080p video.
How do I send a large video from a Mac?: A large video can be sent from a Mac with Mail Drop, which handles attachments up to 5 GB (5,120 MB) per message. Apple's Mail Drop limits page says each attachment expires after 30 days. For normal email, compressing the video to under about 10 MB is the safer choice.
Can I compress a video without lowering the resolution?: Yes, a video can be compressed without lowering the resolution. In QuickTime Player, export at the same 1080p or 4K preset and choose Smaller File Size (HEVC). In iMovie, keep the resolution and lower the bit rate with the Custom quality slider, which shows the estimated file size as it moves.
Is it safe to compress videos online?: Online video compressors work, but every file must be uploaded to another company's server first. A 1 GB (1,024 MB) video can also take a long time to upload on a slow connection. For private or work videos, the built-in Mac tools are safer because the file never leaves the computer.