*{padding: 0;margin: 0} #container{border: 1px solid #000;height:500px;} .left{float: left; background-color: gray; height: 300px; width:200px;} .right{height: 400px; width:300px; background-color: blue;} <div id="container"> <div class="left"></div> <div class="right"></div> </div>