Using aspect-ratio in css with "calc"

I have a div with this css rule:

.somediv {
aspect-ratio: 1 / 3 !important;
}

I want to make the height equal not exactly (3 * width), but plus 8 pixels. For example, if my width is 10px, the height have to be like (10*3)+8 = 38 pixels. How can i do this, i know about calc() in css, but not sure it works with aspect-ratio.

>Solution :

If you are to set a fixed width , you may use CSS var() to set the width, then use calc() for aspect-ratio

examples

:root {
  --width: 80;
}

div {
  margin: 1em;
  border: solid;
  width: calc(var(--width) * 1px);
  aspect-ratio: var(--width) / calc(var(--width) * 3 + 8);
  
  
/* demo purpose */
  float: left;
}

div:before{
content:attr(style);

<div>défault</div>
<div style="--width:100"> </div>
<div style="--width:101"> </div>
<div style="--width:70"> </div>
<div style="--width:90"> </div>

If width is not, then javascriipt will be required