Log in to the dashboard of the website or blog where your video is showing. Click the HTML tab in the top right corner and find your embed code, which will begin and end with: <embed> </embed>
Locate the width and height inside the embed code. Both will be followed by an "equals" (=) sign and a number.
Change the numbers to reflect the size you want your video to be. For example, if the video has a width of 600 and a height of 400 and you want to edit the video size to be smaller, change the numbers to width=400 and height=200. Do not change anything else in the embed code. Click "Publish" or "Update" when you are finished.