Free up iMovie storage

iMovie is iPhone-only. The official iMovie app is not on Android. Projects, trailers, and working copies live on this iPhone. There is no iMovie cloud library. Drafts can be local-only. Apple documents deleting a project, not a WhatsApp-style Free up Storage screen.

See how much space iMovie is using

Open the iPhone Settings app.
Tap General > iPhone Storage.
Tap iMovie.

Documents and Data is the project pile. Offload removes the app binary and keeps that data, so offload alone will not drop a large project total.

Export keepers, then delete projects

In iMovie, tap a project in the Projects browser.
Share / export the finished movie to Photos if you still want the video.
On the project details screen, tap Delete, then tap Delete Project (or Delete Trailer).

Apple says clips and photos you recorded in iMovie while editing that project stay in Photos. Delete those extras in Photos too, including Recently Deleted, if you want the space back.

Originals in Photos

iMovie often points at clips that already live in Photos. The project can still hold a working copy. After you confirm the export, delete the draft in iMovie. Then clean duplicate exports in Photos. Drafts are local-only. There is no iCloud restore for an unsaved project.

Android

There is no official iMovie app on Android. Skip these steps on an Android phone.

iPhone does not offer a separate iMovie cache button. Delete finished projects first. Offload only after you export keepers. Delete App removes local projects.

Reinstall the app if storage is still high

If you already cleaned media and iMovie still looks huge, a fresh install can clear leftover cache and temp files that are hard to reach by hand.

Export finished movies to Photos first. iMovie projects are local-only and are lost if you delete the app. Offload keeps documents. Delete App does not.
Delete the app from your phone.
Restart your phone.
Install iMovie again from the App Store or Google Play.
Sign in and restore from backup if the app offers it.

This often frees a lot of space. You may need to download some media again after restore.

What to do next

After iMovie is lighter, check your photo library for duplicates and similar shots. That is what Dedupo is for.

More app guides: Free up app storage.