Easy conversion of px to ems

gistfile1.scss

// First, set a base size in the document - do this on HTML, or BODY, I tend towards HTML

html {
  font-size: $base-font;
}

// Generally somewhere else (my SCSS is more structured than this, put this function (somewhere before you're going to use it)
@function ems($p, $b: $base-font) {
  @return ($p / $b) * 1em;    /* Because SASS/SCSS allows you to mix units, you can calculate this proportion in pixels, and then  just multiply by 1em to get the o/p in ems */
}