Generated by SassMeister.com.

input.scss

@function length($number, $unit) {
  $strings: 'px' 'cm' 'mm' '%' 'ch' 'pica' 'in' 'em' 'rem' 'pt' 'pc' 'ex' 'vw' 'vh' 'vmin' 'vmax';
  $units:   1px  1cm  1mm  1%  1ch  1pica  1in  1em  1rem  1pt  1pc  1ex  1vw  1vh  1vmin  1vmax;
  $index: index($strings, $unit);

  @if not $index {
    @warn "Unknown unit `#{$unit}`.";
    @return false;
  }

  @return $number * nth($units, $index);
}

@function calculateRem($size) {
  $parentSize : 23px;
  $remSize: $size / $parentSize;
  @return length($remSize,'rem');
}

body {
    width: (calculateRem(16px) - calculateRem(23px) / 5rem);
}

output.css

body {
  width: 0.4956521739rem;
}

settings.json

{
  "sass": {
    "compiler": "dart-sass/1.32.12",
    "extensions": {},
    "syntax": "SCSS",
    "outputStyle": "expanded"
  },
  "autoprefixer": false
}