Memory Foam Pillow Guide: Solid, Shredded and Gel Compared
Memory foam is a slow-rebound polyurethane foam that softens with body heat and pressure, so it holds the shape you press into it instead of springing back. Solid blocks give a fixed contour, shredded fill lets you adjust height, and gel-infused foam is designed to feel cooler at first touch. Choose by height first, then feel, then how the cover washes.
"Memory foam" covers three quite different pillows: a moulded block that holds one shape, a bag of shredded foam you can adjust, and a block with a gel layer that feels cool when you first lie down. They share one material and not much else. This guide explains how the foam behaves, how the three types differ, which suits each sleep position, what the density and height numbers on a listing mean, and how to look after one. At the end, four pillows we stock, one per type, are compared on the facts from their product pages.
Watch the 30-second version on YouTube on the Calm Eden channel.
How memory foam behaves
Memory foam is polyurethane foam made to be viscoelastic: it softens where your body warms and presses it, then returns slowly when you move. That slow rebound is why it cradles the head rather than pushing back like a spring, and why it can feel firm for the first few seconds. Two properties decide how a given pillow feels:
- Density, often written as a D number on listings (for example 50D, about 50 kg per cubic metre). Denser foam is firmer, slower and longer-lasting; lighter foam is softer and quicker.
- Height, the dimension that decides whether your head sits level. Foam barely compresses, so the listed height is close to the height you sleep on. Compare that with a fiber pillow that may squash to half its size.
The three types, compared
| Type | What it is | Feel | Height | Trade-offs |
|---|---|---|---|---|
| Solid contour | A moulded block, usually with a raised neck edge and a head cradle; many have two edge heights | Firm, defined, slow | Fixed; flip for the other edge | Only works if the height matches you; warmest of the three |
| Shredded | Small foam pieces inside a zipped cover; remove or add fill | Conforming, slightly springy | Adjustable | Needs fluffing; fill can clump; no fixed neck roll |
| Gel-infused | A block with a gel layer on top or gel mixed in | Cool at first touch, then like solid foam | Fixed, often several sizes | Cooling effect fades over the night; usually the most expensive |
| Low-profile slab | A thin flat block of foam, often under 5 cm | Firm and flat | Fixed, low | Only for stomach sleepers and people who want almost no loft |
Which type for your sleep position
- Side sleepers need the most height. A contour used on its taller edge, or a shredded pillow with most of the fill left in. Measure your shoulder gap first; see the side-sleeper height guide.
- Back sleepers usually want a lower contour edge with a head cradle, or a shredded pillow with some fill removed. See pillow for back sleepers.
- Stomach sleepers want a low-profile slab or a shredded pillow with most fill removed. See pillow for stomach sleepers.
- Combination sleepers do best with either a two-height contour or adjustable fill. Our adjustable pillow guide explains how to tune one.
- Hot sleepers should look at gel or shredded designs and pair them with a breathable cover; the cooling pillow guide covers what actually helps.
Reading the numbers on a listing
- Height in cm or inches. Some listings give a range ("at least 10 cm and under 15 cm") or two figures for a contour ("7/9 cm" means a low edge and a high edge). Use the edge you will sleep on.
- Density (D). A guide to firmness and durability, not height.
- Size. Standard bed pillows are about 60 × 40 cm (roughly 24 × 16 in) or the US standard 20 × 26 in; queen and king are longer. See the pillow size chart if it must fit a pillowcase you own.
- "Core" versus "with pillowcase". Some supplier listings sell the bare foam core or the core with a case; check which you are buying.
Smell, break-in and lifespan
New polyurethane foam usually has a chemical smell for a day or two after unpacking. Remove all plastic and let the pillow air in a ventilated room; the smell fades on its own. Solid foam also feels firmer in a cold bedroom and softens as it warms under your head, so judge it after a few nights rather than the first one. Over time foam loses its rebound and the head cradle deepens; when the pillow no longer returns to shape after you get up, or the height has visibly dropped, it is time to replace it.
Care
For a step-by-step cleaning routine, see how to wash a memory foam pillow.
- Wash covers only. Read the label: some covers are machine-washable, others hand-wash only.
- Never soak the foam. Spot-clean with a damp cloth and mild soap; let it dry completely, out of direct sun, before covering it again.
- Use a pillow protector under the pillowcase so the cover needs washing less often.
- Shredded foam: fluff weekly and keep the removed fill in a labelled bag.
Four we stock, on the facts
One pillow per type. Even, Flex and Fjord are Calm Eden products; Lowloft is a supplier listing and we only repeat what its page states. All were live and in stock on 28 September 2026.
| Pillow | Type | Listed height / size | Material and care | Price (checked 28 Sep 2026) |
|---|---|---|---|---|
| Even Ergonomic Cervical Pillow | Solid wave contour | Not stated on the listing | Adaptive memory foam; described for back and side sleepers | $49.90 |
| Flex Shredded Foam Adjustable Pillow | Shredded, adjustable | Standard or King; height adjustable, range not stated | Shredded memory foam; care not stated | $49.99 Standard / $54.99 King |
| Fjord Gel Cooling Sleep Pillow | Gel-infused block | Standard 19.7 × 11.8 × 3.9 in; Queen 23.6 × 15 × 4.7 in; King 27.6 × 15.7 × 5.1 in | Cooling gel over supportive memory foam; described for back and side sleepers | $99.90 Standard / $139.90 Queen / $149.90 King |
| Lowloft Low-Profile Memory Foam Pillow | Low-profile slab | Height under 5 cm | Slow-rebound polyurethane memory foam; ice-silk fabric; care not stated | $79.99 |
Four memory foam pillows we stock, one per type
One example of each construction, all live and in stock on 28 September 2026. Three are Calm Eden pillows and one (Lowloft) is a supplier listing described only from its product page.
Before you buy
Decide the height you need first (the pillow-height quiz gives a starting range), then pick the type that delivers it: a contour if you know your number and like a cradle, shredded if you do not, gel if you run hot, a slab if you sleep on your stomach. Check the cover's care label and the return terms: Calm Eden gives every pillow a 30-day risk-free trial, opened or used, per the refund policy. The full range is in the memory foam pillows collection.
Frequently asked questions
Is a memory foam pillow good for side sleepers?
It can be, because foam holds its height under the head instead of collapsing. Side sleepers usually want a contour with a taller neck edge, or a shredded pillow with most of the fill left in. The listed height matters more than the material.
Does memory foam sleep hot?
Solid memory foam is dense and traps more warmth than an open fiber fill. Gel layers, open-cell foams, shredded fill and breathable covers are all designed to reduce that, but none is actively refrigerated. If you run hot, look at gel or shredded options and a cooling pillowcase.
What is gel memory foam?
Memory foam with a gel layer on top or gel particles mixed into the foam. Gel conducts heat away from the skin at first contact, so the pillow feels cooler when you lie down; over a full night the difference is smaller.
What does 50D mean on a memory foam pillow?
It is a density figure, roughly 50 kg per cubic metre. Higher density usually means a firmer, slower-rebounding foam that keeps its shape longer; lower density feels softer and lighter. It says nothing about height, which you should check separately.
Why does a new memory foam pillow smell?
Freshly made polyurethane foam releases a chemical smell, sometimes called off-gassing, that fades over a day or two. Unpack it, remove any plastic and leave it in a ventilated room before the first night.
Can you wash a memory foam pillow?
Wash the cover according to its label, but not the foam. Soaking foam damages it and it can take days to dry. Spot-clean the core with a damp cloth and mild soap, and let it dry fully before putting the cover back on.
Keep reading
- Contour vs regular pillow
- Cooling pillows for hot sleepers
- Adjustable pillow guide
- Shop memory foam pillows
- Cooling pillows
- Pillow-height quiz
Calm Eden sells some of the products mentioned here. Product details come from our own listings; we have not lab-tested them, and comfort varies from person to person. This guide is general information, not medical advice — if you have ongoing pain, numbness, breathing problems at night or a diagnosed condition, talk to a clinician before changing how you sleep.