outerWidth without jquery

No, but you can get offsetWidth, which is probably what you want.

From http://www.quirksmode.org/dom/w3c_cssom.html

offsetWidth and offsetHeight

The width & height of the entire element, including borders and padding (excluding margins).

clientWidth and clientHeight

The width & height of the element including padding (excluding borders and margins)

See this fiddle for an example.

var elm = document.querySelector('div');

document.body.innerHTML += `
  clientWidth: ${elm.clientWidth} px
  <br>
  scrollWidth: ${elm.scrollWidth} px
  <br>
  offsetWidth: ${elm.offsetWidth} px`
  
  

div{
  width      : 200px;
  padding    : 10px;
  border     : 10px solid gold;
  
  margin     : 10px;
  background : lightgreen;
}

<div></div>

If you use jQuery you have more options: width, innerWidth and outerWidth properties. http://api.jquery.com/category/manipulation/style-properties/

Sean provided the perfect solution for outerWidth().

Just to add to that, if you're looking for a substitution for any or all of the jQuery dimension getters related to width, see my solution below.

Note: this also provides the correct dimensions even with * { box-sizing: border-box }

function getWidth(el, type) {
  if (type === 'inner') // .innerWidth()
    return el.clientWidth;
  else if (type === 'outer') // .outerWidth()
    return el.offsetWidth;
  let s = window.getComputedStyle(el, null);
  if (type === 'width') // .width()
    return el.clientWidth - parseInt(s.getPropertyValue('padding-left')) - parseInt(s.getPropertyValue('padding-right'));
  else if (type === 'full') // .outerWidth(includeMargins = true)
    return el.offsetWidth + parseInt(s.getPropertyValue('margin-left')) + parseInt(s.getPropertyValue('margin-right'));
  return null;
}