Convert px values to rem in SASS

rem-calc.scss

$html-base-font-size = 12px;
@function rem( $px ){
  @if( unit( $px ) == 'rem' ){
    @return $px;

  }
  @else if( unit($px) == 'px' ) {
    @return ( $px / $html-base-font-size ) + 0rem;
  }
  @else if( unit( $px ) == '' ) {

    @return ( ( $px + 0px ) / $html-base-font-size ) + 0rem;
  }
  @else {
    @return $px;
  }
}

.example{
  font-size: rem(14px);
  font-size: rem(16); // unitless values are considered to be px
}