A function/mixin set to set up all of your base font sizes in one @include statement.

font-setup-mixin.scss

//EXPONENT FUNCTION
//https://css-tricks.com/snippets/sass/power-function/

@function pow($number, $exponent) {
  $value: 1;

  @if $exponent > 0 {
    @for $i from 1 through $exponent {
      $value: $value * $number;
    }
  }

  @return $value;
}


//FONT SETUP
//change variables to change the scale of base to h1 sizing

@mixin font-setup($base-size, $header-font, $body-font, $font-units, $line-height, $size-ratio) {

  //size ratio references @ http://type-scale.com/

  body {
    font-size: #{$base-size}$font-units;
    font-family: $body-font;
    line-height: $line-height;
  }

  h1, h2, h3, h4, h5, h6 {
    font-family: $header-font;
  }

  h5 {
    font-weight: 700;
  }

  h4 {
    font-size: #{$base-size * pow($size-ratio, 1)}$font-units;
  }

  h3 {
    font-size: #{$base-size * pow($size-ratio, 2)}$font-units;
  }

  h2 {
    font-size: #{$base-size * pow($size-ratio, 3)}$font-units;
  }

  h1 {
    font-size: #{$base-size * pow($size-ratio, 4)}$font-units;
  }

}