Are you wondering how your video will display on YouTube using a different aspect ratio? YouTube is where millions go to get their daily source of entertainment. If you’re a business owner or an aspiring creative and you’re uploading YouTube videos, you’ll need to know the recommended formats and aspect ratios for the platform. If you are uploading on a computer, the standard aspect ratio size is 16:9. If your video has a different aspect ratio display, YouTube will change the video to the standard size. The video player also automatically adjusts to meet the size of your video. For vertical videos, who have an aspect ratio of 9:16, YouTube adds white or dark grey borders to fill the screen. On mobile devices, portrait videos are displayed without black bars to fill the screen on mobile devices. Viewers can press the full-screen button to view the full vertical video. YouTube also features a list of recommended video resolutions, for the 16:9 aspect ratio, so that your videos can be shown at optimal viewing quality!

Credit: Written by YouTube Help YouTube Resolution & Aspect Ratios