How to choose a pillow: a 6-step guide backed by research

The 6 steps at a glance

1. 1

   Know your position

   Side, back, stomach, or a mix. This sets your loft range more than anything else.

2. 2

   Measure your loft

   Fill the gap between your ear and the mattress so your neck stays level.

3. 3

   Choose a firmness

   Side sleepers usually do best with medium-firm to firm, so the head doesn't sink.

4. 4

   Pick a fill

   Latex and shredded foam hold height well, and shredded fills let you adjust it.

5. 5

   Match your mattress

   Soft mattress? Go a little lower. Firm mattress? Go a little higher.

6. 6

   Heat, allergies, care

   Breathable fills, washable covers and a pillow protector extend its life.

Step 1: Identify your sleep position

Your main sleep position decides how high your pillow should be. Side sleepers need the most height, back sleepers need a medium height, and stomach sleepers need very little. Most adults spend over half the night on their side when measured objectively^[1], and self-report surveys put “mostly side” sleepers at over 70%^[5].

Side sleeping becomes more common with age and higher BMI^[1]. People change position about 1.6 times an hour^[1], so if you regularly roll onto your back or front, plan for a combination pillow. Side lying itself is generally associated with fewer waking spinal symptoms than other positions^[6,5].

Step 2: Measure the loft you need

For side sleepers, the right loft fills the gap between your head and the mattress that your shoulder creates. That keeps your nose, neck and spine in one straight line. In lab studies, that gap averaged about 9 cm (3.5 in) from face to shoulder^[7]. A 10 cm (about 4 in) pillow was rated most comfortable, and a 5 cm pillow increased upper-back muscle strain^[8].

One size doesn't fit all. Neck and shoulder muscle activity was lowest when pillow height was scaled to each person's own shoulder measurement^[9], and an individualized height index predicted neck curvature well^[10]. A meta-analysis concluded that alignment in side lying depends more on pillow height and shape than on fill^[11]. In people with neck pain, simply adjusting pillow height to the individual gave half of them a clinically meaningful drop in pain^[12]. That study had no control group and its lead author runs a pillow company, so treat it as encouraging rather than proof.

Use this loft chart

Step 3: Pick a firmness level

Most side sleepers do best with a medium-firm to firm pillow, around 5–8 on a 10-point scale. A soft pillow lets the head sink below the line of the spine as the night goes on. The Sleep Foundation's guidance for side sleepers is firm enough to hold at least 4 inches of height^[2]. Firmness and loft aren't the same thing: a tall, soft pillow can still collapse to 2 inches under your head. See our firm pillow guide if you have broad shoulders or a heavier frame.

Step 4: Choose a fill material

For side sleepers, latex and shredded memory foam are the most reliable fills. They hold their height through the night, and shredded versions let you add or remove fill. In pooled trials, latex (rubber) pillows reduced neck pain more than other types^[11]. In a 106-person field trial of side sleepers, latex performed best and feather worst^[13]. Feather pillows also measurably changed the slope of the neck compared with foam, latex or polyester^[14].

The evidence has limits. A 2025 systematic review of five trials found no pillow type clearly superior for chronic neck pain^[15], and the same meta-analysis found no fill improved sleep quality on its own^[11]. Fill matters, but getting the height right matters more.

Step 5: Factor in your mattress and body

A softer mattress lets your shoulder sink, so you need a lower pillow. A firm mattress needs a taller one. Side-lying spinal alignment changes significantly between soft and firm surfaces^[16], and a sagging mattress worsened sleep for side sleepers in a polysomnography study^[17]. If you're choosing a mattress too, the best low-back-pain evidence favors medium-firm^[18,19]. Broad-shouldered and heavier sleepers usually land at the top of the loft range.

Step 6: Consider heat, allergies and care

Breathable fills and washable covers matter more than “cooling” marketing. Heat increases wakefulness and cuts deep and REM sleep^[20]. Most doctors suggest a bedroom around 65–68°F^[21]. Latex, buckwheat and shredded fills move more air than solid foam. See our cooling pillow guide.

Check the care label before you buy, not after. Solid memory foam usually has to be hand-washed, and latex can't go in a washing machine^[22], so either one needs a washable protector to stay clean. Some shredded-foam and polyester pillows can be machine-washed whole.

Keeping a pillow clean: dust mites, mold and protectors

Pillows build up allergens within months and no fill is immune, so plan to cover yours and wash what's on top of it. New pillows in one study had no detectable dust-mite allergen, but after three months on volunteers' beds, synthetic and buckwheat pillows both averaged about 1.1 µg/g^[23]. Cultures of 10 used pillows found 4 to 16 fungal species in each, with Aspergillus fumigatus in every one, and the synthetic pillows held more species than the feather ones^[24]. Buckwheat has its own issue: new buckwheat pillows carried roughly 12 times the bacterial endotoxin of new synthetic pillows^[23].

Don't count on the fill to protect you. The dust-mite practice parameter from the US allergy societies' joint task force states that foam pillows are no less prone to dust-mite allergen than feather pillows, and that “nonallergenic” pillows are not a substitute for allergen-proof covers^[25]. Allergy to down or feathers themselves is a separate question, covered in our down pillow guide.

What a pillow protector can and can't do

For people with a dust-mite allergy, that guideline recommends mite-proof encasings on pillows, mattresses and box springs^[25]. Choose a tightly woven fabric: a mean pore size under 10 microns blocks the main mite allergen. Nonwoven covers, which look a bit like paper towel, aren't recommended because they trap allergen and can't be washed^[25].

Don't expect a cover alone to fix symptoms. In two large randomized trials, covers cut mite allergen in the bed but didn't improve symptoms on their own: one in 279 people with allergic rhinitis^[26] and one in 1,122 adults with asthma^[27]. The guideline treats covers as one part of a wider plan, not a single fix^[25]. Without allergies, a protector still helps: bacteria, facial oils and dirt build up in a pillow over time^[22], and a cover is easier to wash than the pillow. If you wake congested most mornings, an allergist can test whether dust mites are the cause.

Washing: how often and how hot

Wash pillowcases and protectors weekly with your sheets. Very hot water isn't necessary, says the practice parameter, partly because home hot water above 120°F (49°C) is a scald risk^[25]. In lab tests, water at 131°F (55°C) or hotter killed all mites, and even a cold wash removed more than 90% of the allergen^[28]. The dryer finishes the job: mites seeded into blankets all died after 10 minutes in a clothes dryer^[25]. Keeping indoor humidity between 35% and 50% also slows mite growth^[25]. Wash the pillow itself only as its label allows, and let it dry completely before it goes back in its case.

Pillow sizes explained

Choose the size for your bed and how much you move; choose the loft for your body. Queen and king pillows give restless sleepers more room, and a king is long enough to hug. Match the case to the pillow: a tight case squeezes the fill and costs you height.

Special cases

• Neck pain: prioritize height you can adjust, and consider latex. Best pillows for neck pain →
• Shoulder pain: the down-side shoulder carries more load when side lying^[29]. Use enough loft and hug a second pillow. Shoulder pain picks →
• Sleep apnea / CPAP: 56–62% of people with sleep apnea have the positional type, which is worse on the back^[30,31]. CPAP pillows →
• Acid reflux: left-side sleeping cut acid exposure to a median of 0.0%, versus 1.2% on the right^[32].
• Pregnancy: from 28 weeks, going to sleep on your back was linked to 2.6 times the odds of late stillbirth compared with the left side^[33]. Side sleeping with a body pillow is the usual advice^[34,35].
• Hip or lower-back pain: a pillow between the knees stops the top leg twisting the spine^[36]. Knee pillows →

How to test a pillow (and use the trial)

Give a new pillow at least a few nights, not a few seconds. In side lying, only about 71% of necks had settled within 15 minutes^[3], so a quick test in the store tells you little.

Run a one-week check

Copy the researchers' method. In the largest side-sleeper trials, people slept on each pillow for a week and recorded their waking symptoms every morning^[13,37]. Each morning, note whether you woke with neck pain, neck stiffness, a headache, or pain between the shoulder blades or down the arm, the symptoms those trials tracked^[13,37]. Note anything else that could explain a bad night, too: in one trial, disturbed sleep unrelated to the pillow was common^[37].

Change one thing at a time. Set an adjustable pillow to your measured loft first, then add or remove a small handful of fill and give each change two or three nights. Don't expect a verdict on night one: one owner in our data said it took “two to three weeks to adjust to it and find my fill level”^[38]. If your symptoms are worse at the end of the week than at the start, change the height or try a different pillow.

Know the return rules before you order

A long sleep trial only helps if it covers the place you bought the pillow. Brands that sell direct often offer free trials, but return policies at other retailers may differ from the maker's terms^[22]. On Amazon, most items can be returned within 30 days of delivery if they're in original or unused condition, and each product page shows whether that item is eligible^[39]. A pillow you've slept on is no longer unused, and third-party sellers that ship their own stock handle their own returns^[39]. Read the listing's return terms and the brand's trial terms before you buy. It's also a reason to choose an adjustable pillow: if the height is wrong, you can fix it at home.

When to replace your pillow

Most pillows should be replaced every 1–2 years. Latex lasts longer, and polyester wears out fastest^[4]. Replace yours sooner if it stays folded when you fold it in half, has lumps, or you wake up with a stiff neck. Only 42.5% of side sleepers in one study reported no waking symptoms on their own pillow^[40].