How to Change Aspect Ratio in iMovie - 6 Easy Ways [2024]

The aspect ratio determines the proportional relationship between a video's width and height, making it a key factor for different platforms. Whether you're preparing content for YouTube's 16:9 format or TikTok's 9:16, adjusting your video's aspect ratio is essential. While most devices capture footage in a default ratio, tools like iMovie allow you to customize the aspect ratio to suit various platforms.

In this article, we'll guide you through how to change the aspect ratio in iMovie, including resizing from 16:9 to 9:16, 1:1, 4:5, and more. Learn these simple steps for iMovie aspect ratio adjustments to ensure your videos look perfect on any platform.

The Easiest Way to Change iMovie Aspect Ratio on Mac

Wondershare Filmora is one of the best alternatives to iMovie. It not only includes nearly all the video editing features found in iMovie but also offers more aspect ratio options tailored for modern platforms like 9:16, 3:4, and 1:1. With Filmora, you can easily adjust aspect ratios through basic cropping, zooming&panning, resizing, or even advanced auto-reframing. Here’s how you can do it:

Option 1. Change Video Aspect Ratio via Cropping.

Step 1. Download and open the Filmora video editor on Mac.

Step 2. Open the video you want to edit by clicking on Import on the menu bar. You can also drag and drop the video on your timeline, and your file will open in the Filmora app.

Step 3. To adjust the aspect ratio of your video, click on the Crop option and a pop-up will appear on your screen. Now, you have two options to consider, you can either choose presets aspects ratios of 16:9, 4:3, 1:1, and 9:16, or you can choose custom settings. For custom dimensions, click on Custom and type in your desired ratio.
Additionally, You can also use the Pan&Zoom to motion track specific objects or areas within the frame, keeping your chosen subject in focus at the right aspect ratio.

Step 4. When you are satisfied with the settings, click OK and the aspect ratio of your video will be changed.

Option 2. [Recommended!] Change iMovie Aspect Ratio via Auto Reframing/Resizing.

Step 1. Launch the video editor and select the Auto Reframe feature from the main menu.

Step 2. Upload your iMovie video and choose the desired aspect ratio: Square (1:1), Vertical (9:16), Standard (4:3), Widescreen (16:9), or Cinema (21:9).

Step 3. The AI will automatically detect and track the main subject, cropping and reframing the video to fit the selected aspect ratio while keeping the subject in focus.

Step 4. Preview the reframed video, and if satisfied, click Export to save it in your desired format and resolution.

[Video Tutorial] How to change aspect ratio in imovie on Mac/iPhone/iPad

How to Change Aspect Ratio in iMovie on Mac?

iMovie doesn't have a direct "aspect ratio" setting, but you can adjust the ratio by cropping the video. Here are the step-by-step instructions on on how to change iMovie aspect ratio on Mac for any video project. 

Step 1: Open iMovie and Import Your Video

Launch iMovie, create a new project and import your video by clicking Import Media or dragging the file into the timeline.

Step 2: Select the Clip and Adjust the Aspect Ratio

Click on the video clip in the timeline. To change the aspect ratio in iMovie, use the Crop to Fill tool (crop icon in the top toolbar) to adjust the frame to your desired aspect ratio, such as 16:9 or 9:16.

Step 3: Apply the Crop

After setting the crop frame to the preferred aspect ratio, click Apply. This will update the imovie crop aspect ratio for your project.

Step 4: Export Your Video

Go to File > Share > File to export your video. The adjusted aspect ratio in iMovie will be maintained in the final export.

How to Change Aspect Ratio in iMovie on iPhone?

Here’s how you can aspect ratio of your videos in iPhone using iMovie:

Step 1. Open the video you want to edit in iMovie. You can either choose a pre-existing project or create a whole new one.

Step 2. To change the aspect ratio, tap on the “Zoom” option that you will see in the top right corner of your iPhone screen.

Step 3. You can also use your fingers to resize the video by zooming in or out as required.

Step 4. Tap “Done” and the aspect ratio of your video will be changed.

How to Change Aspect Ratio in iMovie on iPad?

The procedure of changing the aspect ratio on the iPad is quite similar to that of the iPhone. The following steps will help you change the aspect ratio of your videos on iPad using iMovie:

Step 1. Open the iMovie app on your iPad. Import a pre-existing project on your timeline or start a new one.

Step 2. Resize your video by tapping on the “zoom” option.

Step 3. Readjust the video size using your two fingers.

Step 4. Tap “Done” when you are happy with the selected size.

FAQs About Changing Aspect Ratio in iMovie

1. What is the standard aspect ratio for YouTube Videos?

On a computer, the standard aspect ratio for videos on YouTube is 16:9. If your video has a different aspect ratio, YouTube will change it automatically to a size that is suitable for the website. But, it may ruin the quality of the video, or black bars might appear on the sides of the aspect ratio that is too small.

2. What resolution does iMovie support?

The resolution of the first film or video clip that you add to your timeline will define the resolution of your entire iMovie project. The latest versions of iMovie can support 4K and videos with frame rates higher than 30 frames per second.

3. Can I crop a video in iMovie?

Of course, you can crop a video in iMovie. To do so, open a project in iMovie and click on the “Crop to Fill” button. The video will appear in an adjustable frame. Now you can drag the frame and set it to the size you want.

4. How do I change movie dimensions in iMovie 10?

You can only change the size of your movie/video when you share/export your project. Go to the “size” option after clicking on “File” to change the dimensions of your movie.

5. How do I compress videos in iMovie?

Click on the “share” option after clicking on “File”. The video can be compressed for Facebook, Email, Vimeo, and more. Select the option for which you want to compress the file. You may have to make small changes for large videos.

Final Words

Aspect ratio is simply defined as the relationship between the width and height of an image, video, or screen. Various video posting platforms have a standard aspect ratio for videos. So. Before posting your video creation, you have to make sure that the aspect ratio of your video aligns with the website standards.

To tweak the aspect ratio of your videos, you can use iMovie, which is a powerful video editor for Mac and iOS devices. You can also use Wondershare Filmora as the best alternative to iMovie and experience the advanced auto-resizing techniques.