Pillowcases guide
Pillowcase thread count: understand the number before comparing it
Understand pillowcase thread count, yarn ply and the difference from fabric weight. Compare count alongside fibre, weave, finished size and care.
Thread count describes the combined number of lengthwise and crosswise yarns in a measured square inch of woven fabric. It is a construction figure, not a complete score for softness, durability or value. Compare it with the fibre, weave, yarn information, finished size and care before choosing a pillowcase.
Add the two directions; do not multiply them
A woven fabric has lengthwise yarns, called warp, and crosswise yarns, called weft. In a fictional one-inch-square example with 150 yarns in each direction, the combined count is 300. Multiplying 150 by 150 would count crossings rather than give the thread-count figure.
The illustration below shows the two directions without depicting hundreds of tiny threads. Its numbers explain the arithmetic; it is not a microscope image, laboratory count or specification for a real product.
Keep yarn ply separate from thread count
A yarn can contain more than one strand, known as plies. That describes the yarn's construction. It does not make every strand an additional independent yarn in the fabric count.
A historical US FTC staff opinion discusses the risk of inflating a count by multiplying it by the number of plies. This helps explain why a listing should identify count and yarn construction separately. It is not a current legal verdict on a product you are considering or a reason to accuse a seller based on a high number alone.
If the counting basis is unclear, ask how the number was established and whether the yarn is single-ply or plied. Keep the answer with the exact product and version. Missing yarn information remains missing; it cannot be recovered from the price or a close-up photograph.
Compare like with like before comparing bigger numbers
| Information | Question to answer | What a larger count cannot settle |
|---|---|---|
| Fibre composition | Are these the same fibres and blend? | Your preferred surface or whole-item quality |
| Weave | Are both percale, sateen or another construction? | Equivalence between different weaves |
| Yarn disclosure | Is ply or another yarn specification stated? | A missing counting method |
| Finished dimensions | Do both cases fit the intended pillow? | The usable compartment or opening |
| Care | Can you complete both items' documented routines? | Washability from the count alone |
A 300-count percale case and a 400-count sateen case differ in more than one variable. Those two numbers do not isolate why the fabrics may feel different. The percale-versus-sateen guide owns that weave comparison.
Do not convert thread count into fabric weight
Thread count and fabric weight answer different questions. GSM records mass per area. Momme is used for silk fabric weight. Neither can be converted into a reliable thread count just by changing a unit label; yarn thickness and construction also matter.
Do not apply the same thread-count shopping rule to a jersey knit or to every silk listing. Use the momme guide for a silk-weight claim and the jersey-versus-woven comparison when the construction differs.
Decide from the complete listing
Shortlist cases that match your dimensions, material preference and workable care first. Then use count as one disclosed detail when the products are sufficiently comparable. A clear specification can be more useful than a dramatic headline number with no explanation.
This guide does not prescribe a minimum or ideal thread-count range. It also does not rank skin outcomes, cooling or service life. If the case you own fits and meets your preferences, a higher number alone does not identify a reason to replace it.
Evidence and source notes
This guide compares documented specifications and practical buying choices. It does not report a hands-on product test.
- John Lewis: Bed linen buying guide (retailer vocabulary only; checked 2026-10-27). Retailer definitions and its pillowcase measurements, including Oxford size excluding the border. No Irish or global size standard; promotional comfort claims are not adopted.
- Cuddledown Wholesale: Frequently Asked Questions (manufacturer; checked 2026-10-27). Thread-count explanation and the limit of count as a quality indicator. Wholesale commercial terms are irrelevant to this batch.
- FTC: National Textile Association staff opinion (regulator; checked 2026-10-27). Historical US staff discussion of plied-yarn counting and misleading multiplication. It is not a new legal ruling, a current global standard or a quality test of a named product.