How to Choose a Pillow by Sleep Position (Side, Back & Stomach)
The short answer: choose your pillow by the gap between your head and the mattress in your usual sleep position. Side sleepers need a higher, thicker pillow to fill the wide gap at the shoulder. Back sleepers do best with a medium height. Stomach sleepers need a very thin pillow, or sometimes none at all. The goal in every position is the same: keep your head, neck, and spine in a straight, neutral line.
Key takeaways
Matching pillow loft across 3 sleep postures—under 3 inches for stomach, 3 to 5 inches for back, and 4 to 6 inches for side sleepers—keeps your neck neutral:
- Your sleep position decides how much pillow height (loft) you need, because each position leaves a different gap between your head and the mattress.
- Side sleepers want high loft, back sleepers want medium loft, and stomach sleepers want low loft or none, according to the Sleep Foundation.
- Loft is the height of the pillow. Firmness is how much it pushes back. You need enough of both to hold your neck level.
- The wrong height shows up as a stiff neck, a sore shoulder, or waking up to reshuffle your pillow.
- The Pillowash Crisp is a medium-support pillow that fits many back and side sleepers. Strict stomach sleepers usually want something thinner.
Why does sleep position decide which pillow you need?
Sleep position matters because it changes the 2-to-6-inch gap your pillow has to fill. Your spine has a natural curve, and a good pillow keeps your neck lined up with that curve instead of bending it up or down.
The Sleep Foundation puts it plainly: "Choose a pillow with a loft, or thickness, that matches the distance between your neck and your shoulder. This allows your entire spine to stay in a neutral position."
That distance is small when you lie on your back and large when you lie on your side, because your shoulder lifts your head away from the mattress. So the same pillow that feels perfect on your back can feel far too tall on your stomach. Matching loft to position is how you keep the line neutral.
What does pillow loft mean?
Loft is the compressed 2-to-6-inch height of the pillow when your head rests on it, not how firm it feels.
The Sleep Foundation defines it directly: "Loft refers to the height of the pillow – not necessarily the firmness." A high-loft pillow sits tall and fills a big gap. A low-loft pillow stays thin and flat. Loft is the single setting that most affects whether your neck ends up straight or kinked, which is why it leads every recommendation below.
What loft and firmness fit each sleep position?
Here is how loft and firmness line up across the 3 main sleep positions. Use it as a starting point, then fine-tune by feel.
| Sleep position | Loft (height) | Firmness / support | Why |
|---|---|---|---|
| Side | High | Medium to firm | Fills the wide gap between head and mattress at the shoulder, keeping the spine straight. |
| Back | Medium | Medium | Cradles the neck without pushing the head too far forward. |
| Stomach | Low or none | Soft to medium | Keeps the head and neck low so they stay aligned with the spine. |
| Combination | Medium | Medium | A middle height handles back and side time without forcing a kink either way. |
For side sleepers, the Sleep Foundation recommends "a high-loft pillow for support and to fill the space beneath the head and neck." For back and combination sleepers, "mid-loft provides more elevation, and is usually suitable for back sleepers, side sleepers, and those who switch between positions." For stomach sleepers, "low-loft provides a thinner pillow profile... since it keeps the angle of the head and neck low and aligned with the spine."
Should a pillow be firm or soft?
Firmness is a comfort preference, but support is the part that protects your neck, and the two are not the same thing.
A pillow can feel soft on top yet still hold your head at the right height, or feel firm yet collapse flat under your weight. What matters is whether it keeps your neck level all night. Cleveland Clinic frames the standard well: the right pillow "should keep your neck parallel to the mattress, rather than bent down or up," and should be "thick enough to support your head and neck without letting it droop down." A pillow that goes flat by morning is a support problem, not a softness preference.
How do you know your pillow is the wrong height?
The clearest signs of a 1-to-2-inch loft mismatch show up in the first 30 minutes each morning.
If you wake up with a stiff neck, a sore shoulder, or a dull ache at the base of your skull, your pillow may be holding your head too high or too low. Another tell is fidgeting: if you fold your pillow in half, stack a second one on top, or yank it out from under your head during the night, you are compensating for the wrong loft. Cleveland Clinic notes that a stiff neck "is almost always a temporary symptom of overusing your neck or sleeping in an unusual position," and a poorly matched pillow can put you in that position for hours at a stretch.
A quick check: have someone look at you from the side while you lie in your normal position. Your nose should point straight ahead and your neck should run in a straight line with your spine, not tipped up toward the ceiling or dropped toward the bed.
Can the wrong pillow cause neck pain?
A pillow can play a role in how your neck feels, because it sets your head and neck angle for 7 to 8 hours every night, and an angle that bends the neck up or down can leave it stiff by morning.
A pillow that matches your position helps keep your neck aligned, which is one piece of comfortable, restful sleep. It is not a treatment, though. If neck pain keeps coming back, lasts more than a couple of weeks, or interferes with your day, see a doctor to rule out an underlying cause. A new pillow is worth trying, but it is not a substitute for medical advice. If you get frequent morning aches above the neck too, our note on the wrong pillow and headaches covers what else to check.
Where does the Pillowash Crisp fit?
The Pillowash Crisp is a medium-support pillow, sized 24 x 16 x 4.8 inches. Its core blends food-grade silicone with reticulated foam, so it holds its shape and springs back instead of flattening out, and it stays breathable thanks to Breath-Real™ construction. Because the support is steady rather than soft-and-sinking, it tends to suit back sleepers and many side sleepers who want a pillow that keeps their neck level through the night.
To be honest about fit: strict stomach sleepers usually want a very thin pillow, so a medium-support pillow like the Crisp is the least likely match for that group. We would rather tell you that up front than promise it works for everyone. If you sleep on your back or side and want a washable pillow that keeps its shape, the Pillowash Crisp comes with a 30-night trial, so you can sleep on it and decide for yourself. And because it is fully washable, keeping it clean is straightforward.
Frequently asked questions
What pillow height is best for side sleepers?
Side sleepers do best with a 4-to-6-inch high-loft pillow. Lying on your side creates the widest gap between your head and the mattress because your shoulder lifts your head away from the bed, so you need extra height to fill that space and keep your spine straight. The Sleep Foundation recommends "a high-loft pillow for support" for side sleepers.
What kind of pillow is best for stomach sleepers?
Stomach sleepers do best with a very thin, low-loft pillow, or sometimes no head pillow at all. A tall pillow forces the neck to bend upward when you lie face down. A thin one keeps the head and neck low and aligned with the spine. This is also why a medium-support pillow is usually not the right pick for strict stomach sleepers.
Does pillow firmness or loft matter more?
Loft, the height of the pillow, matters most for keeping your neck aligned, because it sets the angle of your head. Firmness then determines whether the pillow holds that height all night or collapses under your weight. You want enough loft for your position and enough support to keep it there until morning.
Is the Pillowash Crisp good for back sleepers?
The Pillowash Crisp is a medium-support pillow, and steady medium support suits many back sleepers who want their head cradled without being pushed too far forward. Whether it is right for you depends on your body and mattress, which is why it ships with a 30-night trial so you can test it at home.
How long should you try a new pillow before deciding?
Give a new pillow at least a couple of weeks of regular use. Your body needs time to adjust to a different height and support level, and one or two nights is not enough to judge. The Pillowash Crisp includes a 30-night trial so you have time to know for sure.
This article is for general information and is not medical advice. If you have persistent or worsening neck pain, please see a doctor.
Related guides
Find the right 3-to-5-inch loft for side or back sleeping: take our 30-second Pillow Health Check, check dimensions in the Pillowash Care FAQ, or try the 30-night trial on the Pillowash Crisp Washable Pillow: