A pillow that looks generous on the bed can feel too high once you lie down. A thinner one can lose enough height under your head to leave your neck feeling unsupported. The starting point is your position in bed, rather than a universal number of inches.

Lie on your usual mattress, let your shoulders settle, and notice whether your head feels level with your body. You should not need to hold your head in place or brace your neck to feel comfortable.

Check the height where you actually sleep

Do this on your normal mattress with the pillowcase you use at night. A showroom mattress, a hand pressed into the fill, and the height printed on a package cannot reproduce your whole setup.

Settle for a few minutes. If someone can help, ask them to look at your head and neck from the side or behind. Use the observation as a comfort check, not a posture diagnosis. If adjusting the pillow makes you feel worse, stop.

If you sleep on your side

Your pillow needs to occupy the gap between your head and the mattress after your shoulder has sunk in. If your head drops toward the bed, try a little more support. If it tilts away from the mattress, try a little less.

Keep your shoulder on the mattress rather than stacking it on top of the pillow. A soft bed may allow more shoulder sink than a firm one, changing the gap even if you use the same pillow.

Wider shoulders do not automatically mean you need a particular loft. Consider shoulder sink, the firmness of the filling, and your own comfort together. Our side-sleeper guide walks through those tradeoffs.

If you sleep on your back

Notice your chin. If the pillow pushes it toward your chest, a lower profile may feel easier. If your head tips back or your neck feels as if it is spanning an empty gap, redistribute the filling or try a different shape.

A folded towel can briefly help you explore a small change. Keep adjustments modest and remove it if it creates pressure or discomfort. Do not stack several pillows and assume that more height means more support.

If you change positions

Check the two positions you use most. A pillow that feels comfortable on your side but pushes your head forward on your back may be too tall or too firm for your combination of positions.

You may prefer an adjustable filling or a more compressible feel. Change a small amount, sleep with it, and reassess before changing the mattress, pillow, and sleeping position at the same time.

Make the next adjustment small

If your pillow opens, set removed fill aside in a clean, closed bag. Spread the remaining filling evenly and close the zipper before testing. Keep loose filling away from children and pets.

Check the pillow fit tool for a starting direction. You can also compare how different fillings compress in our memory foam and down guide.

When the pillow is only part of the picture

Neck discomfort has several possible causes. A pillow experiment cannot identify them. The NHS advises getting help for persistent neck pain or additional symptoms such as pins and needles. Use medical advice when you need it instead of repeatedly buying a higher or firmer pillow.

Sources & further reading

These resources inform the general health guidance in this note. They do not endorse Siestly or establish a clinical benefit for our pillow.