Generated by SassMeister.com.

input.scss

@function font($tag: p, $size: 15, $scale: 1.333) {
    @if($tag == p or $tag == h4 ){
        $result: $size; 
        @return #{ceil($result)}px;
    } @else if($tag == h3 or $tag == h5) {
        $result: $size * $scale; 
        @return #{ceil($result)}px;
    } @else if($tag == h2) {
        $result: $size * $scale * $scale;
        @return #{ceil($result)}px;
    } @else if($tag == h1) {
        $result: $size * $scale * $scale * $scale;
        @return #{ceil($result)}px;
    } @else {
        $result: $size;
        @return #{ceil($result)}px;
    }  
}


@for $i from 1 through 5 {
    h#{$i} {
      font-size: font(h#{$i});
      line-height: 1.7;
    }
}

output.css

h1 {
  font-size: 36px;
  line-height: 1.7;
}

h2 {
  font-size: 27px;
  line-height: 1.7;
}

h3 {
  font-size: 20px;
  line-height: 1.7;
}

h4 {
  font-size: 15px;
  line-height: 1.7;
}

h5 {
  font-size: 20px;
  line-height: 1.7;
}

settings.json

{
  "sass": {
    "compiler": "libsass/3.5.5",
    "extensions": {},
    "syntax": "SCSS",
    "outputStyle": "expanded"
  },
  "autoprefixer": false
}