HTML

how to find out how big an elemnts totla width is in css

<div>
  To find the total width of an element use the following formula: width +
  left padding + right padding + left border + right border + left margin 
  + right margin. This element has a width of 350px based on the fomula.
</div>


<style>
  div {
    width: 320;
    padding: 10px;
    border: 5px;
    margin: 0px;
  }
</style>