The proportional relationship between a video's width and height is the aspect ratio and this will determine how the video will look on various players.

You will learn in this article how to use iMovie to adjust the aspect ratio of your video.

Quick Navigation

  1. How to use Movavi Video Editor to Convert Aspect Ratio More Effectively
  2. Changing Aspect Ratio Using iMovie on Mac
  3. How to use iMovie on iPad/iPhone to Change Aspect Ratio

Before We Begin Please Note:

Before we begin, please note that iMovie 10 or later versions have widescreen (or 16:9) aspect ratio.

Custom resolutions are NOT supported. Only videos with the following resolutions can be edited and exported in iMovie:

  • 1920×1080 (1080p)
  • 1280×720 (720p)
  • 960×540 (540p)
  • 854×480 (480p)

Note: these aspect ratios are all 16:9. You have the option to insert black borders or use iMovie to crop/frame the video so that it could be used in another video editing tool.

If you want to use aspect ratios of 1:1, 9:16 or 21:9, then iMovie is not to tool to use in those instances.

1. Convert Aspect Ratio More Effectively Using Movavi Video Editor

Movavi Video Editor is a user-friendly and flexible slideshow maker and video editor and is compatible on both PC and Mac computers.

Use this software to effortlessly do basic video editing. Movavi also includes advanced video editing tools like Chroma Key Effect, Time-lapse and image stabilization.

Movavi also comes with a library that contains hundreds of amazing filters, overlays, text and motion elements, which are updated regularly. All of these tools help to you create amazing videos.

With the video aspect ratio converter, you can permanently alter the video's aspect ratio to be compatible with your target gadget. Movavi is compatible with 1:1, 4:3, 9:16, 16:9 or any other custom aspect ratio you require:

Step1. Download Movavi Video Editor and install it on your PC.

Step2. Import video to be edited into Movavi.

From the folders where the video clips are stored on your computer, just drag and drop them into the video editor.

Step3. Adjust the Video's Aspect Ratio

On the right side, just below the preview window, there is a drop-down menu with various video aspect ratio options.

Pick from the standard ones provided or customize the video width and height to your needs.

The most popular presets have been calculated for your reference along with their respective aspect ratio values.

Or you can use one of the online aspect ratio calculators to calculate the missing width and height pixels.

2. Changing Aspect Ratio using iMovie on Mac

As outlined earlier, iMovie does not allow you to customize video aspect ratios.

One option is to edit and save the video in iMovie as usual and then upload that video into another video editor like Keynote to edit the aspect ratios.

For newbie editors, this process is somewhat complex, but it works.

Find out below how to use Keynote to adjust video aspect ratios:

To begin with, Use iMovie to Edit and Export Your Video as Usual:

Begin by editing your video in iMovie as usual. When you finish the editing, export it in widescreen format.

This makes the video 16:9 aspect ratio.

Now, use Keynote to adjust the aspect ratios:

Launch Keynote and make a new slide by choosing the White theme:

Remove the default text inside the slide:

Next, drag and drop the video from iMovie onto this screen:

When the video is in, head to the top right corner and select Document. Choose Slide Size and from the drop-down menu, choose Custom Slide Size:

In the box, input the custom Width and Height numbers. For instance, say you want a1:1 square video, just input 1024 and 1024.

Do you want a different aspect ratio? Calculate those values using the online aspect ratio calculator.

Final step is to Export the video from Keynote:

Head to "File" -> "Export" and choose to export to QuickTime. In the popup window, input the export settings and click "Next".

When the export is completed, use QuickTime to preview the final video.

3. How to use iMovie on iPad/iPhone to Change Aspect Ratio

Do you want to adjust the aspect ratio on your iPad or iPhone using iMovie? That option isn't available at the moment.

A video editing app like Filmorago is an alternative for the iPad and iPhone.

Although this app is free, there are in-app features available for purchase. This is one of the best video editing apps available and is compatible with Android and iOS.

With Filmorago you can produce subtitles and text, trim videos, speed up clips, insert overlays and filters, include audio etc. There are 2 aspect ratios available: 1:1 or 16:9. This means you are able to switch either from 1:1 or 16:9.

How to Change Aspect Ratio in iMovie (Updated for 2020)

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Hey, My name is Paul – nice to e-meet you 🙂 I'm a freelance video editor who has over 4 years experiences of making all types of videos. I founded this website to provide step-by-step and easy-to-follow instructions to first-time editors or beginners like you who want to start their journey in video editing.