# Sleep Align

> Independent pillow research covering sleep ergonomics, pillow loft and neck pain. Not a clinical practice and not staffed by clinicians.

All datasets, charts and tools listed here are free to reproduce, redraw, embed or quote under CC BY 4.0 with a link back to the source page. No permission needed.

Method: specifications come from manufacturers' own published pages, with the source URL recorded per row. This site does not buy, test, weigh or sleep on the products it writes about and never claims to. Where a figure is not published, it is recorded as missing rather than estimated.

## Datasets

- [Pillow Loft & Specification Database](https://sleepalign.org/pillow-specification-database/): Published loft, fill, firmness, adjustability, cooling claim, trial window, warranty and price for 32 pillows sold in the US, each row sourced to a manufacturer page. Of these, 16 publish a loft measurement and the rest publish none.
  - CSV: https://sleepalign.org/data/pillow-specifications.csv
  - JSON: https://sleepalign.org/data/pillow-specifications.json

## Tools

- [Pillow Height Calculator](https://sleepalign.org/pillow-height-calculator/): Computes the supported pillow loft a body needs from sleeping position, frame width and mattress firmness.
  - API: https://sleepalign.org/wp-json/sleepalign/v1/loft?position=side&build=average&firmness=medium
  - OpenAPI: https://sleepalign.org/data/openapi.json
- [Sleep Quiz](https://sleepalign.org/sleep-quiz/): Routes a sleeper to the loft range and guide that match their position, build and mattress.

## Reference

- [Sleep Reference](https://sleepalign.org/sleep-reference/): Hub for the citable reference assets: datasets, charts and models, all CC BY 4.0.
- [Sleep Position & Pain Map](https://sleepalign.org/sleep-position-pain-map/): Side, back, stomach and combination sleeping mapped to the pillow loft each needs on soft, medium and firm mattresses, with the mechanical reason and a source per claim.

## Condition guides

- [Best Pillow for Recliner Sleeping](https://sleepalign.org/best-pillow-for-recliner-sleeping/): Neck support when the sleeping surface is a reclined chair rather than a flat mattress.
- [Best Pillow for Cervical Stenosis](https://sleepalign.org/best-pillow-for-cervical-stenosis/): Loft and position for narrowing of the cervical canal, side sleepers in particular.
- [Best Pillow for Pinched Nerve in Neck](https://sleepalign.org/best-pillow-for-pinched-nerve-in-neck/): Cervical radiculopathy: what changes the traction on the nerve root overnight.
- [Best Pillow for Cervical Spondylosis](https://sleepalign.org/best-pillow-for-cervical-spondylosis/)
- [Best Pillow for Military Neck](https://sleepalign.org/best-pillow-for-military-neck/): Loss of cervical lordosis and why a high pillow makes it worse.
- [Best Pillow for Degenerative Disc Disease in the Neck](https://sleepalign.org/best-pillow-for-degenerative-disc-disease-neck/)
- [Best Pillow for Occipital Neuralgia](https://sleepalign.org/best-pillow-for-occipital-neuralgia/)
- [Best Pillow for Frozen Shoulder](https://sleepalign.org/best-pillow-for-frozen-shoulder/)
- [Best Pillow After Cervical Fusion (ACDF)](https://sleepalign.org/best-pillow-after-cervical-fusion/)
- [Best Pillow for Shoulder Pain](https://sleepalign.org/best-pillow-for-shoulder-pain/)

## Pillow fundamentals

- [How to Choose a Pillow for Your Sleep Position](https://sleepalign.org/how-to-choose-a-pillow-for-your-sleep-position/)
- [Pillow Firmness Guide](https://sleepalign.org/pillow-firmness-guide/)
- [Memory Foam vs Latex Pillow for Neck Pain](https://sleepalign.org/memory-foam-vs-latex-pillow-for-neck-pain/)
- [Buckwheat vs Memory Foam Pillow](https://sleepalign.org/buckwheat-vs-memory-foam-pillow/)
- [How Often Should You Replace Your Pillow](https://sleepalign.org/how-often-should-you-replace-your-pillow/)
- [How Long Does a New Pillow Take to Stop Hurting Your Neck](https://sleepalign.org/how-long-new-pillow-stop-hurting-neck/): The adaptation window, and how to tell adaptation apart from a pillow that is simply the wrong height.

## Key facts

- Supported pillow loft = ear-to-mattress gap minus shoulder sink. A softer mattress needs a LOWER pillow, not a higher one, because the shoulder sinks further into it.
- Side sleeping computes to roughly 3.5-6.25 in and back sleeping to roughly 2.75-4.4 in, before a +/- 0.5 in tolerance band.
- Stomach sleeping is treated as a fixed 1-2 in; no loft makes the position good for the neck.
- Loft figures are not comparable across fill types: down and down-alternative heights are published uncompressed and collapse under load, while moulded foam and latex barely compress.

## Full text

- https://sleepalign.org/llms-full.txt

## Contact

- hello@sleepalign.org for corrections, raw figures behind any table, or the calculator as an embed.