Pillow firmness is one of the most misunderstood pillow specifications because it is entirely subjective. What one brand calls “firm” another calls “medium.” What feels firm to a 55 kg person feels soft to a 95 kg person. Without standardised firmness testing in the UK pillow market, buyers must navigate conflicting descriptions and personal preferences to find a firmness that suits their sleeping position and body weight. Here is how to cut through the confusion and find the right firmness for you.
Why Firmness Matters
Firmness determines how much the pillow compresses under your head’s weight, which directly affects loft (compressed height). A soft pillow compresses significantly, reducing the effective loft. A firm pillow resists compression, maintaining more of its original height. Your ideal firmness depends on how much compression you need to achieve your target loft for your sleeping position.
Side sleepers need firm pillows that resist compression to maintain the high loft (12 to 16 cm) needed to fill the shoulder-to-neck gap. A soft pillow compresses too much under the concentrated weight of a side sleeper’s head, losing critical height. Back sleepers need medium firmness that allows moderate compression for comfortable cradling while maintaining medium loft (8 to 12 cm). Stomach sleepers need soft firmness that compresses nearly flat, providing minimal loft to avoid neck extension.
Coop Home Goods Original Adjustable Pillow
Firmness by Material
Memory Foam
Memory foam firmness is determined by density. Under 40 kg/m³ feels soft, 40 to 55 kg/m³ feels medium, and above 55 kg/m³ feels firm. Memory foam also feels firmer when cold and softer when warm (it responds to body heat), so the initial feel when lying down differs from the feel after 10 minutes. Test memory foam pillows for at least five minutes before judging firmness.
Latex
Latex firmness varies between Dunlop (firmer, denser) and Talalay (softer, bouncier) processing methods. ILD (Indentation Load Deflection) rating measures latex firmness: under 20 ILD is soft, 20 to 30 is medium, and above 30 is firm. Most latex pillow manufacturers do not publish ILD ratings, but specifying Dunlop or Talalay processing gives a reliable firmness indication.
Down and Feather
Down and feather firmness depends on the down-to-feather ratio. Higher down percentages (80%+ down) create softer pillows. Higher feather percentages (40%+ feather) create firmer pillows because feather quills provide structural resistance that down clusters do not. Fill weight also affects firmness — more fill in the same cover creates a denser, firmer pillow.
Polyester and Microfibre
Polyester firmness depends entirely on fill weight and fibre type. Hollowfibre (tubes with air cores) is firmer and bouncier than solid fibre. Siliconised fibres feel softer and more slippery than untreated fibres. Fill weight is the strongest firmness indicator: under 500 grams is soft, 500 to 700 is medium, and above 700 grams is firm for a standard size pillow.
Buckwheat
Buckwheat hull pillows are inherently firm. The rigid hulls interlock to create a solid, stable surface. Removing hulls reduces height but does not significantly soften the feel — even a half-filled buckwheat pillow feels firmer than most foam or fibre alternatives.
Body Weight and Firmness
Heavier sleepers compress pillows more than lighter sleepers, which means the same pillow feels softer to a heavier person. A “firm” polyester pillow that maintains adequate loft for a 60 kg side sleeper may compress too much for a 90 kg side sleeper, losing the height needed for proper alignment.
As a general guide, sleepers under 60 kg can use medium firmness for side sleeping and soft for back sleeping. Sleepers between 60 and 85 kg should follow standard firmness recommendations (firm for side, medium for back). Sleepers above 85 kg should choose firm or extra firm for side sleeping and medium-firm for back sleeping. Adjustable pillows accommodate any body weight by allowing fill adjustment to achieve the exact compression needed.
The Firmness-Comfort Balance
Some sleepers need firm support for alignment but find firm pillows uncomfortable against their face. Hybrid pillows with firm foam cores and soft fibre outer layers solve this by providing structural firmness underneath with surface softness on top. The core maintains loft while the outer layer provides a comfortable contact surface.
Memory foam naturally provides this balance because its heat-responsive surface softens where the face contacts while the cooler interior remains firmer. The result is a pillow that feels softer than its overall firmness rating would suggest because the contact layer adapts while the support layer holds.
Sijo FlexCool Shredded Memory Foam Pillow
Testing Firmness Before Buying
In-store testing is the most reliable way to assess firmness, but most pillow packaging prevents hands-on testing. Shops with display pillows (John Lewis, Dreams, Dunelm) allow you to feel the firmness and test by lying down. When buying online, look for specific firmness indicators (foam density, fill weight, ILD rating) rather than subjective labels. Many online retailers offer trial periods (30 to 100 nights) that let you test at home and return if the firmness is wrong.
For further guidance, our neck pain guide explains how firmness affects cervical alignment. Our budget and luxury guides recommend specific products across the firmness spectrum at different price points.
| Pillow | Best For | ||
|---|---|---|---|
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Coop Home Goods Original Adjustable Pillow | Best value adjustable | View |
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Sijo FlexCool Shredded Memory Foam Pillow | Best for hot sleepers | View |
Teresa created SaunaReviewer.com after discovering how transformative sauna therapy was in her own life. Today, she helps thousands of readers find reliable, honest information about saunas, accessories, and at-home wellness. Her mission is to make choosing the right sauna easier, clearer, and stress-free.
