.container { position: relative; overflow: hidden; width: 100%; padding-top: 56.25%; /* 16:9 Aspect Ratio (divide 9 by 16 = 0.5625) */ } /* Then style the iframe to fit in the container div with full height and width */ .responsive-iframe { position: absolute; top: 0; left: 0; bottom: 0; right: 0; width: 100%; height: 100%; }