What Is Momme Weight In Silk? The Number That Tells You How Good It Really Is

Q: What is the difference between 19 momme and 22 momme silk?

19 momme silk is lighter and softer but less durable. 22 momme is heavier, about 13 grams per square metre more, and holds up better through regular washing.

Q: Is 30 momme silk worth it?

It depends on your priorities. 30 momme is more substantial and durable than 22 momme, so it is worth it if longevity matters most.

Q: What is Grade 6A silk?

Grade 6A is the highest commercially available silk quality, made from long, unbroken, lustrous filaments. It produces a smoother, more consistent fabric.

Q: Can high momme silk be machine washed?

Yes, if the care label permits. 22 momme and 30 momme silk can typically be machine washed on a cold delicate cycle with a mesh laundry bag and pH-neutral detergent.

Lunelle Team

24 June 2026

6 min read

If you are shopping for a silk pillowcase and finding that every product listing mentions momme weight without ever explaining what that actually means, you are in good company. Momme is the correct measurement for silk quality, and understanding it takes about two minutes. After that, the comparison between a 19 momme pillowcase and a 22 momme one will make immediate sense.

Quick Answer

Momme (mm) is a weight measurement for silk fabric. It tells you how much a standard piece of silk weighs: a higher number means heavier, denser, more durable fabric. For a silk pillowcase, 19 to 22 momme is the standard range. 22 momme is the recommended choice for most people: durable enough for regular washing, soft enough for comfortable sleep. 30 momme is the premium option for those who want extra durability and a more substantial feel.

Key Takeaways

Momme is a weight measurement for silk. Higher momme means heavier, denser, more durable fabric.
22 momme is the sweet spot for most silk pillowcases: durable enough for regular washing without being heavy or stiff.
Thread count is the wrong metric for silk. Momme is the correct one. A high thread count on a silk listing is a marketing number, not a quality signal.
Momme tells you the weight. It does not tell you the silk grade (look for 6A), the weave (charmeuse gives the smooth finish), or whether it has been tested for harmful residues (look for OEKO-TEX certification).

What Does the Number Actually Mean?

Momme is a Japanese unit of weight. For silk specifically, it measures the weight in pounds of a piece of fabric at 45 inches wide and 100 yards long. In practice, you do not need to remember that formula. What matters is the conversion to more familiar terms: one momme equals approximately 4.34 grams per square metre. So a 22 momme silk pillowcase has a fabric weight of roughly 95 grams per square metre, and a 30 momme pilllowcase weighs around 130 grams per square metre.

Those numbers become meaningful when you compare silk to other fabrics. A lightweight cotton t-shirt might be around 130 to 150 grams per square metre. Quality cotton bedding typically runs 130 to 200 grams per square metre. Silk at 22 momme is noticeably lighter, but it is not fragile: the continuous filament structure of mulberry silk gives the fabric strength and durability that does not scale linearly with weight the way woven cotton does.

Expert Insight Silk's continuous filament structure is what makes it different from cotton and synthetic fibres. A silkworm produces one unbroken thread that can run up to 1,500 metres long. That unbroken filament is what creates silk's smooth surface, its natural sheen, and its tensile strength at lower fabric weights. Weight and strength do not track the same way in silk as they do in cotton weaves. For more on how mulberry silk compares with other fibres, our guide to what mulberry silk actually is explains the fibre science in full.

Which Momme Is Right for a Silk Pillowcase?

The useful range for pillowcases runs from 19 momme to 30 momme. Below 16 momme, silk is too sheer and too fragile for regular bedding use. Above 30 momme, the fabric is better suited to upholstery or heavyweight garments. Here is how the pillowcase-relevant weights compare.

Momme	Weight (approx.)	Feel and durability	Who it suits
19 mm	~82 g/m²	Light and very soft; less durable over time. Fine for occasional use.	Light sleepers; occasional or guest use
22 mm Recommended	~95 g/m²	Noticeably soft without being fragile. Holds up well to regular machine washing.	Most people for everyday nightly use
25 mm	~109 g/m²	More substantial feel; slightly less drapey than 22 mm. Good durability.	Those wanting extra durability without going to 30 mm
30 mm	~130 g/m²	Noticeably heavier and more structured. Very durable. A premium investment.	Those who prioritise longevity and a more substantial feel above softness

For most people buying a silk pillowcase for daily use, 22 momme is the right choice. It is durable enough to wash weekly without thinning, soft enough to feel genuinely different from cotton, and priced at a point that makes two pillowcases (the minimum for rotating covers through a standard laundry cycle) practical. If durability is the priority above all else, our full guide to the 30 momme option compares both weights in detail.

Lunelle 22 Momme Mulberry Silk Pillowcase

Momme vs Thread Count: Why Thread Count Does Not Apply to Silk

Thread count is a cotton metric. It measures how many threads are woven per square inch of fabric. For cotton, a higher thread count (up to a point, around 400 to 600) generally correlates with a softer, more tightly woven fabric. Silk does not work this way for two reasons. First, silk filaments are far finer than cotton fibres, so a given thread count means something entirely different in terms of fabric density. Second, silk's quality comes from the filament itself, not how many strands are woven together.

When you see a high thread count on a silk listing, it is a marketing number. The correct quality signals for silk are momme (weight and density), grade (look for 6A, the highest commercially available purity), and weave. For pillowcases, charmeuse weave is the standard: it produces a smooth, reflective finish on one side and a matte finish on the reverse. For more context on what determines silk pillowcase quality, our guide to what silk pillowcases actually do covers the evidence on each quality claim.

What Silk Pillowcases Actually Do

The strongest evidence is for friction reduction. Silk's smooth surface creates significantly less friction against hair than cotton, which has a rougher fibre surface that catches on hair cuticles. The American Academy of Dermatology recognises silk pillowcases as a practical way to reduce mechanical stress on hair during sleep, which can contribute to breakage and frizz over time. If you want the full analysis of which silk pillowcase has the best results for hair, our guide covers the best pillowcase for hair in detail.

Skin benefits are more modest than marketing often implies. The Cleveland Clinic notes that a smooth pillowcase surface may reduce overnight facial compression creases. Claims that silk "prevents wrinkles" or "improves skin" are not well supported by clinical evidence. Silk also does not absorb skin oils the way cotton does, which is useful if you apply skincare before bed.

Frequently Asked Questions

What does momme mean in silk?

Momme (abbreviated mm) is a weight measurement for silk fabric. It expresses the weight in pounds of a standard piece of silk measuring 45 inches wide by 100 yards long. A higher momme number means the fabric is heavier, denser, and generally more durable. For pillowcases, the useful range is 19 to 30 momme, with 22 momme being the most common everyday choice.

Is 22 momme silk good quality?

Yes. 22 momme is the recommended weight for a silk pillowcase used regularly. It is heavy enough to be durable across repeated washing, soft enough to feel markedly different from cotton, and at a weight that does not feel stiff or heavy against the face. Most quality silk pillowcase brands use 22 momme as their standard offering.

What is the difference between 19 momme and 22 momme silk?

19 momme silk is lighter and softer but less durable. It is better suited to occasional use or for those who prioritise the lightest possible feel. 22 momme is heavier by about 13 grams per square metre, holds up better through regular machine washing, and is the better choice for nightly use on a standard sleep schedule.

Is 30 momme silk worth it?

It depends on your priorities. 30 momme silk is noticeably more substantial and more durable than 22 momme. If longevity is your primary concern, or if you are replacing pillowcases frequently and want something that will last significantly longer, 30 momme is worth the premium. If you want the softest, lightest feel, 22 momme is the better choice. Our full comparison is in the 30 momme guide.

Does thread count matter for silk?

No. Thread count is a cotton metric and does not translate meaningfully to silk quality. For silk, momme weight is the correct quality indicator. When a silk listing emphasises thread count, treat it as a marketing number rather than a genuine quality signal.

What is Grade 6A silk?

Silk is graded A, B, or C based on filament quality, and within the A grade, further classified from 2A to 6A. Grade 6A is the highest commercially available quality: long, unbroken, lustrous filaments from the best part of the cocoon. It produces a smoother, more consistent fabric that maintains its surface quality longer than lower grades. Look for Grade 6A alongside the momme weight when evaluating a silk pillowcase.

Can high momme silk be machine washed?

Yes, if the care label permits. Both 22 momme and 30 momme silk can typically be machine washed on a cold delicate cycle with a mesh laundry bag and a pH-neutral enzyme-free detergent. Higher momme weight is slightly more forgiving of the washing process, but the same care rules apply: cold water, low spin, no biological detergent, no tumble dryer.