Knee pillow vs body pillow vs a regular pillow

Nell, the Side Sleeper
Updated October 9, 2026 · Data collected October 5, 2026 · How we research

A knee pillow does one job, keeping your knees apart, in a block about the size of a paperback. A body pillow is around four feet long. You hug it and hook a leg over it, so it holds up your knees, arm and shoulder at once, and it takes up a lot of bed.

A regular pillow folded between your knees is the free version of either. Try it first. If it's flat or on the floor by morning, that's your sign to buy something made for the job.

Rumpled white pillows and sheets on an unmade bed. — Photo: Jay Mantri / StockSnap

Side by side

	Knee pillow	Long / full-leg pillow	Body pillow	Regular bed pillow
Typical size	10 × 7.9″, 5–7.2″ thick	26 × 10.5″, 3–6.5″ thick	47 × 10 × 10″	26 × 20″, loft varies
Weight	About 15 oz	About 30 oz	5.1 lb	Varies
What it holds up	Your knees	Thigh and knee, or knee to ankle	Knees and lower legs, plus your top arm and shoulder	Whatever you fold it into
Stays put?	Not always. A strap helps	Mostly, because your leg lies along it	Yes, because you're wrapped around it	Slides and flattens
Turning over	Easy to take with you	Takes a bit of shuffling	Heavy to haul to the other side	Easy, if it hasn't fallen out
Price	$17–$45, typically $31	$23–$47, typically $37	$36 for the one in our table	You probably own one

Knee and long-pillow figures are medians and ranges across the best sellers in the comparison table, from the listings that give each number. The body pillow is a single example, the TranquilRelax C-Shaped Body Pillow 47". Prices are from October 5, 2026 and change daily.

Footprints to scale, seen from above. The body pillow is C-shaped in use but is drawn straight here so you can compare lengths.

When a body pillow is the better buy

Your top shoulder or arm is the problem too. If you wake with your top arm numb, or your shoulder rolled forward, a knee pillow can't help. Something to hug can.
You like the hug. That's a fine reason. Plenty of people sleep better with something to hold.
You mostly stay on one side. Hauling 5.1 lb of pillow across the bed every time you turn gets old.

The catches are bed space, heat (it's against a lot more of you), and the fact that its thickness between the knees isn't really yours to choose. The one in our table is 10″, which is taller than any fixed-height compact knee pillow. Shredded fill helps, because you can take some out.

When a knee pillow is the better buy

Only your hips or lower back complain. That's the knee pillow's whole job.
You turn over a lot. At about 15 oz, it comes with you.
You share the bed, or simply don't want half of it given over to a pillow.
You need a particular height. Knee pillows come in a range of thicknesses, and the towel test tells you which one you need.

Try a regular pillow first

Before spending anything, fold a pillow you already own in half and put it between your knees. Then do the level-thigh check. If it works and stays put, you may not need to buy anything. Give it a week.

You've outgrown the free version if:

it's flat by morning and your hip aches by then
it's on the floor when you wake
it's too big and bunches up in front of you, or too much for your knee gap even when folded

The first two point to a firmer knee pillow, maybe with a strap (see how to use one). The third points to a compact one sized to your gap.

Quick answers

What is a knee pillow?

A small, firm pillow, usually memory foam about 10 by 7.9 inches, that goes between your knees when you sleep on your side. It stops your top leg sliding forward and down, so your hips, pelvis and lower back stay lined up.

Are knee pillows any good?

For a side sleeper whose top knee drops toward the mattress, a pillow between the knees is mainstream advice: the NHS suggests one to keep your legs in line with your hip joints. A dedicated knee pillow only beats a folded regular pillow if it holds the right height all night and stays where you put it, so try the free version first.

Should I get a knee pillow or a body pillow?

A body pillow suits you if you like hugging something, want your top arm and shoulder supported too, and have the bed space. A knee pillow suits you if you only need your knees apart, turn over often, or share the bed.

Sources

Pillow between the legs to keep them in line with the hips: Greater trochanteric pain syndrome, NHS inform.
Knee, long and body pillow sizes, weights and prices: Amazon US listings and manufacturer pages, collected October 5, 2026. See knee pillows compared.
Bed pillow size: the common US "standard" pillow size. Pillows vary by brand.