Eleven or thirteen centimetres is unloaded height, not a prescription. Foam and mattress compression change the working height.
Start around 11 cm when alternating side and back or with average shoulders. Reserve 13 cm for a larger side-sleeping gap on a firmer mattress.
What pillow height measures
Published height is unloaded. Density, temperature and shape change compression.
A softer mattress lets the shoulder sink and reduces the gap.
Signs of too much or too little
From the side, observe whether head and torso remain reasonably aligned. A tall back-sleeping pillow can push the chin towards the chest.
Also note breathing, ear pressure and ease of changing side.
Why 11, 12 and 13 cm appear here
Fityou is a simple 9/11 wave; HOMCA adds a centre recess at 8/12; SAHEYER offers 11/13 for a larger gap.
All sat in a mid-price ergonomic band with substantial review histories when checked.
Evidence and limits
The studies below guide the decision; they do not validate a product listing or replace individual clinical advice.
Small laboratory studies comparing heights from 8 to 17 cm show that height changes pressure and alignment. A 2025 side-sleeper study linked shoulder width to individual height. These are useful mechanical clues, not proof that 11 or 13 cm is best for everyone.
Quick questions
Can 11 cm work for side sleeping?
Yes, depending on shoulder width, mattress sink and final alignment.
Is 13 cm too high?
It can be for back sleeping or narrow shoulders; it suits a larger side gap.
Three heights and shapes doing different jobs
Fityou 9/11 cm
A simple wave with 9 and 11 cm edges to choose the support height that suits you.
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