How to Compress a Video in iMovie

iMovie makes a video smaller when it exports the project. Trim footage you do not need, open the file export dialog, and reduce the resolution or quality. Keep the project and original clips until you have watched the exported copy.

Compress a video during iMovie export

These steps apply to iMovie on Mac:

1. Open the project and remove unused footage from the beginning, end, or middle of the timeline.
2. Click the Share button, then choose File. You can also use File > Share > File from the menu bar.
3. Keep Format set to Video and Audio unless you only need the soundtrack.
4. Choose a lower Resolution. Start with 1080p for a 4K project or 720p for a small review copy.
5. Change Quality from Best to High, Medium, or Low. Avoid Best (ProRes) when file size is the priority.
6. Choose a Compress option. This setting changes the time iMovie spends converting the project, while resolution and quality are the clearer controls for output size.
7. Check the estimated file size shown in the export dialog.
8. Click Next, choose a different filename from the source, and save the export.

Apple’s current iMovie export instructions confirm that lowering resolution or choosing Medium or Low quality produces a smaller MP4 export. Available values can depend on the source media and project.

Trimming is the only size reduction that does not lower the quality of the frames you keep. If the video has 30 seconds of setup or a long pause, remove that before changing image quality.

Choose the right iMovie export settings

Do not lower every setting at once. Change the setting that matches the destination, export a short test when practical, and inspect it.

Destination	Starting point	Check closely
Large screen or client review	1080p, High quality	Faces, gradients, camera motion
Chat, ticket, or email	720p, Medium quality	UI text and captions
Very small reference copy	540p or 720p, Low quality	Whether text remains readable

Resolution controls the number of pixels in each frame. Reducing 4K to 1080p removes much more image data than a small quality adjustment, so it is often the most effective first step.

Quality influences how much data iMovie gives the encoded video. Medium can be appropriate for a review copy, but footage with fast motion, particles, foliage, or detailed screen text may need High.

Compress is a speed and encoding-effort choice, not an exact megabyte control. iMovie shows an estimate, but it does not let you enter a hard output size. If a portal accepts no more than a specific number of megabytes, leave room below the limit rather than aiming at it exactly.

Check the result before deleting anything

Open the exported file outside iMovie and review three points: a detailed frame, the fastest motion, and the quietest audio. Confirm that captions remain legible and that the full video plays through.

Then check the file in Finder with Get Info. If it is still too large, return to the project and change one setting at a time:

• Trim more footage if the message survives without it.
• Move from 1080p to 720p if the destination is a small screen.
• Move from High to Medium quality if resolution must stay unchanged.

Keep the iMovie project and source clips as the editing master. Repeatedly importing and exporting an already compressed file introduces another lossy encoding pass and can make artifacts more visible.

When iMovie cannot reach your target size

iMovie is an editor with useful export controls, not a target-size compressor. Its limits matter when you need to process several separate videos, reuse the same settings every week, choose a specific codec, or meet an exact upload cap.

If the destination accepts links, sharing the full-quality file through an approved file service may be better than making text unreadable. If the destination requires an attachment, use a dedicated target-size video workflow rather than repeatedly guessing between iMovie presets.

For a single project that already needs editing, iMovie is sufficient. There is no reason to export the project once and run another lossy pass unless the first export misses a real size or compatibility requirement.

Compress finished videos with GetCompress

GetCompress fits the part of the workflow that begins after editing. Drag in finished MOV, MP4, and other video files, preview and trim them, then compress them locally without rebuilding an iMovie timeline.

Choose a simple quality level such as High or Medium, and GetCompress calculates suitable quality, speed, preset, and related settings for the selected codec and format. It supports AV1, H.265, H.264, and many other codecs, while still allowing detailed control when you need it.

It is useful when you need to queue a batch, save a reusable delivery preset, or set a target file size for video. iMovie remains the right tool for arranging clips, titles, transitions, and sound. GetCompress handles repeatable delivery copies when the edit is already complete.

Before sending a compressed copy, compare it with the source using the synchronized video comparison tool and inspect the same frames in both versions.