I have a dynamic width
Code used in this page
.calc { width: 100px; height: 100px; border: 1px solid #f00; padding: 10px; /* Firefox */ width: -moz-calc(75% - 100px); /* WebKit */ width: -webkit-calc(75% - 100px); /* Opera */ width: -o-calc(75% - 100px); /* Standard */ width: calc(75% - 100px); }