How to change video aspect ratio on Mac and PC?

The aspect ratio of video refers to the proportional relationship between its width and its height. 4:3 is the standard video aspect ratio for TV sets, 16:9 is the video aspect ratio for HD TVs and widescreen displays. They are the two common video aspect ratios. Every video has its original aspect ratio in which the film is originally produced. To gain better visual experience, you can alter the original video aspect ratio according to your display screen. There are different ways to convert aspect ratios. You can enlarge original video to fill the area and cut off excess area, you can also stretch video image to fill in the area according to new ratio. If not properly handled, videos will be distorted when you altered its aspect ratio. Is there any way to easily change video aspect ratio on Mac and PC computer? In this quick guide, we will show you how to edit video aspect ratio from 4:3 to 16:9, change aspect ratio from 16:9 to 4:3 quickly for novice.

How to change video aspect ratio on Mac and PC?

Firstly download the media converter on to your Mac or Windows computer below. It has the required video conversion and aspect ratio conversion capabilities to help us change video aspect ratios. It comes with both Windows and Mac versions, choose according to your computer OS.

Find your source video file on your computer, then drag and drop it from its folder to the media editing program on your Mac or PC.

convert and edit videos on computer

You will see an Edit button besides each video clip added to the video converter. Click on this button to open the video editing window. It will default to the Trim tab. Switch to Adjust tab, you can then find the Aspect Ratio setting. See below screenshot.
change video aspect ratio on computer

Now you can crop videos on your Mac or PC computer, or change aspect ratios to 16:9, 4:3, Letterbox, Pan & Scan, Full screen. You can easily edit video aspect ratio from 4:3 to 16:9, change movie aspect ratio from 16:9 to 4:3, etc. Another fix to change video size, resolution or aspect ratio is to play the source video using a media player or an online video in web browser, then scale up or down the video player window to any size or aspect ratios you like, then record the streaming video while it is playing.

If you do not know the best video aspect ratio or would like to know if any easier ways to do that, you can simply ignore the video aspect ratio change instructions above. For example, if you want to play videos on iPhone, you can refer to this guide to convert videos to iPhone, this video converter has the optimized video profiles and settings for the device or hardware, so you do not need to change anything manually. It is the same for TV sets and other players.

Note that video aspect ratio is different from video resolutions. The resolution of an image or video file is the total number of pixels displayed on your computer or television screen. If you did not see any dramatic image quality downgrade, you do not need to care about video resolution. We encourage you to examine the video aspect ratio question before other aspects like resolution, brightness, contrast, video quality, and so on.