<div class="box calculate-from-width-and-height">
  <p>width & height</p>
</div>

<div class="box calculate-from-width">
  <p>width</p>
</div>

<div class="box calculate-from-height">
  <p>height</p>
</div>

.box {
  align-items: center;
  background-color: rgb(19 78 74 / 0.1);
  color: rgb(55 65 81);
  display: flex;
  font-size: 0.625rem;
  justify-content: center;
  margin: 1rem auto;
}

.calculate-from-width-and-height {
  aspect-ratio: 1 / 1;
  height: 8rem;
  width: 6rem;
}

.calculate-from-width {
  aspect-ratio: 1 / 1;
  width: 6rem;
}

.calculate-from-height {
  aspect-ratio: 1 / 1;
  height: 6rem;
}