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 resolution or quality. Keep the project and original clips until you have watched the exported copy.

Compress during iMovie export

These steps apply to iMovie on Mac:

1. Open the project and remove unused footage from the timeline.
2. Click Share, then File, or use File → Share → File.
3. Keep Format set to Video and Audio unless you only need audio.
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 matters.
6. Note the Compress option: it mainly changes how long encoding takes. Resolution and Quality drive size more clearly.
7. Check the estimated file size in the dialog.
8. Click Next, pick a new filename, and save.

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

Trimming is the only size cut that does not lower quality of the frames you keep. Remove setup time and long pauses before you touch image quality.

Choose export settings that shrink the file

Change one lever at a time. Match the destination, export a short test when you can, and inspect it.

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

Resolution sets pixels per frame. Dropping 4K to 1080p usually saves more than a small quality step.

Quality controls how much data the encode keeps. Medium suits many review copies; fast motion, foliage, or detailed screen text may need High.

Compress is not an exact megabyte control. iMovie shows an estimate, but you cannot type a hard output size. Leave headroom under portal limits rather than aiming at the cap exactly.

Check the result before you delete anything

Open the export outside iMovie. Scrub a detailed frame, the fastest motion, and a quiet audio section. Confirm captions stay readable and the file plays through.

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

• Trim more if the message survives without that footage
• Move from 1080p to 720p for small screens
• Move from High to Medium if resolution must stay

Keep the iMovie project and source clips as the editing master. Re-importing and re-exporting an already compressed file adds another lossy pass.

When iMovie cannot reach your size

iMovie is an editor with useful export controls, not a target-size compressor. Limits show up when you need several finished videos, the same settings every week, a specific codec, or an exact upload cap.

If the destination accepts links, share the full-quality file through an approved service instead of crushing text. If it requires an attachment, use a dedicated target-size video workflow rather than guessing between iMovie presets.

For a single project that still needs editing, stay in iMovie. Do not export once and run another lossy pass unless the first export misses a real size or compatibility need.

After editing, compress finished files with GetCompress

GetCompress fits the step after editing. Drop finished MOV or MP4 files, preview and trim if needed, then compress locally without rebuilding an iMovie timeline.

Choose a simple quality level, or set an exact video target file size when the form lists a megabyte limit. Queue a batch, save a delivery preset, and keep masters untouched. iMovie remains the right tool for clips, titles, transitions, and sound. GetCompress handles repeatable delivery copies when the edit is done.

Compare source and export with the video comparison tool before you send. For broader Mac routes, see how to compress video on Mac .