Pillow Height Calculator: Find Your Correct Loft in 30 Seconds

Pillow loft reference table

Every result the calculator can produce, published in full so you do not have to run it. The figure is the supported height under your head once the pillow has compressed — not the loft printed on the packaging. For memory foam, add roughly half an inch to the box figure, because it compresses under the weight of your head.

The method behind these figures: supported loft = the ear-to-mattress gap measured lying on your side without a pillow, minus how far the shoulder sinks into the mattress. Mattress sink is taken as 1.5 in for soft, 0.75 in for medium and 0.25 in for firm, halved for back sleeping because less shoulder is involved. Starting gaps where nothing is measured: narrow build 5.0 in side / 3.5 in back, average 5.75 / 4.0, broad 6.5 / 4.5. Results are given as a ±0.5 in range because loft tolerance is real. Stomach sleeping is treated as a fixed 1–2 in, because no loft figure makes that position good for the neck.

This table and the calculator are free to quote, cite or embed with attribution to Sleep Align. It is a practical model built from pillow-loft conventions and cervical-alignment principles, not a clinical measurement — treat the output as a starting range to test.

Why pillow height matters more than anything else about a pillow

Firmness, fill material and cooling all get more attention, but height is the variable that decides whether your neck spends the night in a neutral position or a strained one. A pillow that is an inch too high holds your head bent forward for seven hours. An inch too low and it drops sideways instead. Either way the same muscles are loaded all night, every night — which is why the pain is reliably worst in the first hour after waking.

The reason so many people buy a well-reviewed pillow and still wake up sore is that loft is personal. It depends on how wide your shoulders are, which position you sleep in, and how much your mattress lets you sink. A pillow that is genuinely correct for a broad-shouldered side sleeper on a firm mattress will be roughly two inches too tall for a narrow-framed back sleeper on a soft one.

The mattress variable nobody accounts for

This is the part that catches people out. On a soft mattress your shoulder sinks into the surface, which closes part of the gap the pillow would otherwise need to fill. The softer the bed, the less pillow you need — the opposite of most people's instinct.

It also explains a common experience: buying the right pillow, then getting a new mattress and finding the pillow suddenly wrong. Nothing changed about the pillow. The amount your shoulder sinks did.

The size of that shift is worth knowing before you replace a mattress: for a side sleeper it is 1.25 in between soft and firm, which is two and a half times the tolerance this calculator allows. Our sleep position and pain map sets out every position-and-firmness combination, what goes wrong mechanically when the pillow stays the same, and what the published research does and does not support about pain in each position.

Testing your result

Give any new height a full week. Your neck adapts to whatever position it has been held in, so a correct pillow can feel mildly wrong for the first two or three nights. What you are looking for after a week is the first hour after waking — if the stiffness has eased, the height is right. Our free seven-night sleep diary is built for exactly that week — it records morning pain and the position you woke in alongside how long you actually slept, so you are judging written-down nights rather than an impression. If it has not changed at all, you are probably out by more than half an inch, or the problem is not the pillow. Which direction you are out in shows up in observable signs, and whether your pillow is too high or too low sets out what each sign points to. Not every night-time symptom is a pillow-height problem, and the night-time symptom reference sets out which ones are: 50 symptoms against the position and mechanism each is associated with, including the 13 for which no published source describes any bedding change at all.

For a fuller breakdown of the other causes, see our guide to what causes morning neck pain and how to work out which one applies to you.

Use this calculator on your own site

Physiotherapists, chiropractors, ergonomics consultants and sleep writers are welcome to embed this tool free of charge. Copy the code below, or click Embed this calculator above. The only condition is keeping the attribution link. It is built as a single self-contained page that runs entirely in the browser — no signup, no tracking, nothing sent to a server — the same way the offline tools at sumikiri.online are built, which is where this one came from. If you would like it adapted for your own patients or audience, get in touch through our contact page.

<iframe src="https://sleepalign.org/pillow-loft-calculator-embed/" width="100%" height="860" style="border:1px solid #e2e8f0;border-radius:12px" title="Pillow Height Calculator by Sleep Align" loading="lazy"></iframe>
<p style="font-size:13px;color:#64748b">Calculator by <a href="https://sleepalign.org/pillow-height-calculator/" target="_blank" rel="noopener">Sleep Align</a></p>

Once you have your number, check it against the actual pillows. Our Pillow Loft & Specification Database records the published loft, trial window and warranty for 32 pillows straight from their manufacturers’ pages — and shows which of them fall inside the range calculated above. Only 16 of the 32 publish a height at all. Both this calculator and that dataset are free to reuse with attribution; see the Sleep Reference Library.