A half moon pillow is a bolster cut in half, flat on one side and rounded on the other. The flat side keeps it from rolling, and it is small enough to move between your knees, under your legs, behind your lower back or behind your neck.
This guide covers where to place a half moon pillow and what to look for in one. It also covers six pillows that are in stock on the web US.
Disclaimer: This article is general information, not medical advice. A pillow cannot treat pain. If you have neck, back, hip or knee pain, or leg swelling, talk to your doctor or physical therapist about the right position and support for you.
Half moon pillow basics
- Cleveland Clinic suggests a pillow between the knees when you sleep on your side, to stabilize your hips so they do not twist.[1]
- If you sleep on your back, a pillow under the knees flexes the hips and lets the low back relax.[1]
- Cleveland Clinic says people with back or neck pain often find relief sleeping on their back with a pillow as a bolster under the knees.[2]
- For back pain in pregnancy, the NHS suggests keeping your back straight and well supported when sitting, and looking for maternity support pillows.[3]
- Pick the size by use. A compact bolster fits under both knees, and a longer one suits a massage table or a recliner.
Key Specs
| No. | Product | Type | Fill / material | Cover | Sizes | Care |
|---|---|---|---|---|---|---|
| 1 | Noverlife Massage Bolster | Bolster | Foam | PU leather, zippered | 21.2 x 6.1 x 3 in | Wipe clean |
| 2 | ComfiLife Knee Bolster | Memory foam pillow | Memory foam | – | 17.3 x 7.8 x 4 in | Cover is machine washable |
| 3 | Cushy Form Half Moon Bolster | Memory foam pillow | Memory foam | – | 22.1 x 8.7 x 5.1 in | Cover is machine washable |
| 4 | 5 Stars United Knee Bolster | Memory foam bolster | Memory foam | – | 20.4 x 7.8 x 4.8 in | Cover is machine washable |
| 5 | ComfortHome Leg Elevation | Memory foam pillow | Foam, no memory foam | – | 16 x 7.5 x 4 in | Cover is washable |
| 6 | Beeveer Moon Shaped | Decor pillow | PP cotton | Cotton | 23.6 in | Machine washable |
– = not stated by the maker. Specs as stated by the maker, not tested by us.
The Half Moon Pillow and Its Uses
A half moon pillow combines the roles of a knee pillow, a leg pillow and a small lumbar pillow in one shape. You can use it in several places:
- Between the Knees – Dr. Andrew Bang, a Cleveland Clinic chiropractor, says that if you sleep on your side and feel twisting in your low back, a pillow between your knees stabilizes your hips instead of letting them twist. He calls it a wonderful trick.[1]
- Under the Knees – If you sleep on your back and your legs lie flat, your low back can arch too much. A pillow under your knees flexes your hips and lets your low back relax, he says.[1] See our knee pillows for more.
- Lower Back – Use it as a lumbar pillow behind your back in a chair or recliner. The NHS suggests keeping your back straight and well supported when sitting.[3]
- Under the Ankles – Raise your feet for a rest. The compact picks below are low-profile, so they raise the legs only slightly.
- Portable – Most picks are slim and light enough to carry.
What to Look for in a Half Moon Pillow
Half moon pillows come in different sizes, so match the size to the job. A compact one of about 16 to 21 inches sits under both knees. A longer one of about 22 to 26 inches suits a massage table or a full-length side sleeping position.
- Fill – Memory foam holds its shape under your legs, and some picks use other foam for a cooler feel.
- Firmness – Medium-firm foam keeps your knees or back supported without flattening.
- Cover – A removable, washable cover with a zipper keeps the pillow clean. Look for a non-slip finish if you use it on a chair.
- Size – A bolster that is too tall pushes your knees up too far, and one that is too low does little.
- Certifications – Some covers carry OEKO-TEX Standard 100 certification for the fabric.
Our Picks: Half Moon Pillows
Here are six half moon pillows that are in stock on the web US.
We hope you love the products we recommend!
We may collect a share of sales or other compensation from the links on this page. This does not change your price.
1
Noverlife® Massage Bolster PU Leather Half Round Bolster
Currently unavailable
The Noverlife Massage Bolster is a half-round foam bolster made for massage tables, and it also works under the knees or neck.
- It is flat on one side so it does not roll, with a strap handle for positioning.
- The soft PU leather case zips off and is water and oil resistant, so you can wipe it clean.
- It measures 21.2 x 6.1 x 3 inches, and the foam insert ships vacuum sealed.
2
ComfiLife® Knee Bolster Low-Profile Memory Foam Half Moon
Currently unavailable
The ComfiLife Knee Bolster is a compact half-moon pillow of medium-firm memory foam that sits under both knees.
- It measures 17.3 x 7.8 x 4 inches, a low-profile bolster for back sleepers rather than a full-leg wedge.
- The high-density foam holds its shape, and it can also go between the knees, under the ankles or behind the neck or lower back.
- The breathable cover is machine washable.
3
Cushy Form® Half Moon Bolster Memory Foam Lumbar and Leg Bolster
Currently unavailable
The Cushy Form Half Moon Bolster is a larger memory foam bolster for the lower back, knees and legs.
- It measures 22.1 x 8.7 x 5.1 inches and suits side, back and stomach sleepers.
- The memory foam is made for long-term, frequent use.
- The cotton cover is removable. Wash it on a delicate cycle and dry it on low.
4
5 Stars United® Knee Bolster Memory Foam Half Moon Bolster
Currently unavailable
The 5 Stars United Knee Bolster is a memory foam half-moon pillow for back sleepers who want support under the knees.
- It supports the knees, legs, hips and ankles when you lie on your back, and also works between the knees or under the ankles.
- The standard size is 20.4 x 7.8 x 4.8 inches, and the foam contours to your legs.
- The brand states that the American Chiropractic Association endorses it.
- The anti-pill cover is OEKO-TEX Standard 100 certified, comes off for washing and has replacements sold separately.
5
ComfortHome® Leg Elevation Non-Slip Half Moon Bolster
Currently unavailable
The ComfortHome Leg Elevation is a small half-moon pillow with a non-slip cover and no memory foam.
- It measures 16 x 7.5 x 4 inches and goes under your knees, thighs or ankles, or behind your back in a recliner.
- The non-memory-foam fill is made to stay cool.
- The cover grips the chair or bed and is removable and washable.
- The seller offers a lifetime refund guarantee.
6
Beeveer® Moon Shaped Plush Decor Half Moon Pillow
Currently unavailable
The Beeveer Moon Shaped is a decorative plush crescent pillow, not a support pillow. Keep it out of any infant’s sleep space.
- It is about 23.6 inches long with a soft plush cover and PP cotton fill.
- It suits a couch, bed or reading corner as a back cushion.
- It can be machine washed on a cold, gentle cycle, and ships vacuum sealed, so fluff it and let it sit for 3 to 7 days.
How We Chose These Pillows
These picks come from research. We compared the makers’ specifications, the The web product pages and buyer feedback, and we checked that every pick is in stock on the web US. We did not test the pillows ourselves.
We looked at these factors:
- Shape and Size – Whether the bolster is the right length and height for your use.
- Support – Whether the foam holds its shape under your legs.
- Cover – Whether it is removable and washable, with a zipper.
- Use – Whether it works for sleeping, sitting or massage.
Frequently Asked Questions (FAQ) About Half Moon Pillows
- Where do I put a half moon pillow when I sleep?
On your side, put it between your knees to stabilize your hips. On your back, put it under your knees to relax your low back.[1] - What is a half moon pillow used for?
People use them under the knees, between the legs, behind the lower back and under the ankles. Massage therapists also use half round bolsters on massage tables. - Can a half moon pillow relieve back pain?
Cleveland Clinic says people with back or neck pain often find relief sleeping on their back with a bolster under the knees.[2] A pillow does not treat the cause, so see a doctor if pain continues. - What size half moon pillow should I buy?
A compact bolster of about 16 to 21 inches sits under both knees. A longer one of about 22 to 26 inches suits a massage table. - Can I use a half moon pillow in pregnancy?
The NHS suggests maternity support pillows for back pain in pregnancy.[3] Ask your midwife or doctor which support suits you.
Index Table: Halfmoon Pillows
| No. | Product | Image | Features | Brand |
|---|---|---|---|---|
| 1 | Noverlife Massage Bolster - PU Leather Half Round Bolster |  |
| Noverlife |
| 2 | ComfiLife Knee Bolster - Low-Profile Memory Foam Half Moon |  |
| ComfiLife |
| 3 | Cushy Form Half Moon Bolster - Memory Foam Lumbar and Leg Bolster |  |
| Cushy Form |
| 4 | 5 Stars United Knee Bolster - Memory Foam Half Moon Bolster |  |
| 5 Stars United |
| 5 | ComfortHome Leg Elevation - Non-Slip Half Moon Bolster |  |
| ComfortHome |
| 6 | Beeveer Moon Shaped - Plush Decor Half Moon Pillow |  |
| Beeveer |
Sources
- Cleveland Clinic. Sleeping Positions: Tips to Wake Up Pain-Free. Accessed October 26, 2026.
- Cleveland Clinic. The Best Sleeping Positions for a Restful Night. Accessed October 26, 2026.
- National Health Service (NHS). Back pain in pregnancy. Accessed October 26, 2026.
Update History
- Oct 2026: Rewrote the article around Cleveland Clinic and NHS guidance on sleeping with a pillow between or under the knees, removed the claims about effective pain relief and endless benefits, rewrote all six product notes and replaced the Sources
- Oct 2026: Removed Saloniture Half Round Bolster (unavailable)
- Oct 2026: Replaced unavailable products: Beautiful Life pain releif Pillow with Noverlife Massage Bolster; Bekweim Multi-Position Pillow with Saloniture Half Round Bolster; wavveUziz Bolster Pillow with Beeveer Moon Shaped Pillow
- Oct 2026: Removed Coop Home Goods 4 position Pillow, Skyzonal Memory Foam Pillow and Abco tech Bolster Pillow (unavailable)
- Oct 2026: Added a Key Specs comparison table and a Sources section, removed first-person testing claims
- Aug 2020: Added wavveUziz Bolster Pillow
- Feb 2020: Added Cushy Form Half Moon Bolster, 5 Stars United Knee Bolster, ComfortHome Leg Elevation Half Moon Pillow and Bekweim Multi-Position Pillow
- Nov 2019: Published
