Smart Video Enlarger is a free Google Chrome Extension that automatically scales YouTube videos to the size of the browser window–or slightly smaller if you prefer to read the video comments along with the video.
By default the videos enlarge to 100% but you can select a ratio from 30-100% in order to allow for comment reading. It’s a nice feature but most people will likely leave it at 100%. Smart Video Enlarger is free and works wherever Google Chrome does. Hit up the link below to grab a copy. Curious about the video in our screenshot? You can watch it here.