If you change the width and height dimensions in the IFRAME, be sure to recalculate the ratio for the padding-bottom in the surrounding DIV. I used the size dimensions in your code to figure out the ratio: 569 / 960 * 100 = 59.27% and I also converted the CSS code into an inline style for you: What you need is a responsive embed! Check out and you can plug in your code under generic iframe. Looking at your code, I take it that's what you got from Google when you click Publish to Web? And you're trying to get rid of the black bars on the top and bottom when the size of the browser window changes, right?