Find your pillow loft

The logic is simple. Side sleepers need a pillow that fills the gap between the ear and the mattress — and that gap is basically your shoulder width when you lie down. Broader shoulders need more loft. A softer mattress lets the shoulder sink in, which shrinks the gap, so you need a little less. If you also sleep on your back, you want the lower end plus adjustability, so the pillow compresses when you roll.

This is an estimate to get you in the right range, not a medical measurement. The surest test is still the mirror one: lying on your side, your nose should line up with the center of your chest, with your head neither tipped up nor sagging down.