What Is Momme? Silk's Unit of Weight, Explained

Momme is the unit that shows the weight of silk fabric, abbreviated “mm”. One momme equals roughly 4.3 grams per square metre. As momme rises, fabric generally becomes denser, more opaque and more durable; sleepwear most often uses between 16 and 25 momme.

Where does the word momme come from?

Momme comes from monme, a traditional Japanese unit of weight that is still used for pearls. In textiles, momme is defined as the weight in pounds of a piece of silk 45 inches wide and 100 yards long. If a piece of that size weighs 19 pounds, the fabric is 19 momme.

In everyday terms: momme tells you how heavy the silk is over a given area. More silk in the same area means a higher momme. It works like the grams-per-square-metre figure used for cotton or polyester, just in a different unit.

How much is momme in grams?

One momme is roughly 4.3 grams per square metre. If you are used to fabric weights in grams, here are the approximate equivalents:

The figures are rounded. Sources calculate the conversion with small differences, but this table is enough to compare fabrics.

How to read a momme figure

If a product description says “22 mm” or “22 momme”, that is the weight of the fabric. Here mm is not millimetres but the abbreviation for momme; the fabric is not 22 millimetres thick. This mix-up is common.

If no momme is given, you can ask the seller. If no figure is available, judge the fabric in the hand and in the light: how much of your hand shows through when you hold it up to the light, how much weight it has in your palm, how it falls on a hanger. These three observations are what momme means in practice.

Some products give grams per square metre instead of momme. To compare, divide the gram figure by 4.3; the result is the approximate momme.

Is momme the same as thread count?

No. Thread count is used mostly for cotton bed linen and tells you how many threads there are in a given area. It is not a common measure for silk; silk fabrics are compared by momme. If a silk product highlights a high thread count, ask for the momme and the weave instead.

What does momme determine?

Thickness and opacity

Low-momme silk can be thin and semi-sheer, especially in light colours. As momme rises, the fabric lets less light through. The difference is clear in a light-coloured, unlined nightdress; in dark colours it is less noticeable.

Drape

Weight changes how fabric falls. Higher momme flows down more heavily and straight, following the line of the body more calmly. Lower momme floats more lightly and moves more with you. In long bias-cut pieces, heavier fabric hangs with more balance.

Durability

With the same weave and the same quality of yarn, more silk means more durability. Higher momme stands up better to friction, washing and thinning over time. That matters for a piece you wear and wash often.

Warmth

Thicker fabric holds a little more heat. The difference is not large, but choosing lighter silk for summer and heavier silk for winter makes sense. For choosing by season, see are silk pyjamas hot in summer.

Price

Momme is, quite simply, the amount of silk. As momme rises, so does the raw material, and so does the price. A simple calculation: a 22 momme fabric contains more than a third more silk per square metre than the same weave at 16 momme.

Which momme for sleepwear?

Most silks used in sleepwear fall between 16 and 25 momme. Each value in that range answers a different need:

• 16 momme: light and cool. Suits summer nightdresses and fine linings. Light colours may be slightly sheer.
• 19 momme: a balance between lightness and durability. Common in nightdresses and pyjamas.
• 22 momme: more opaque, with a heavier drape. A frequent choice for long nightdresses, pyjamas and robes.
• 25 momme and above: dense and heavy. Robes, winter nightdresses and pieces expected to last a long time.

The cut affects the choice too. In a strappy, bias-cut nightdress the fabric touches the skin directly and you feel every gram. A robe, worn on top, carries a heavier fabric comfortably. Light colours such as ecru, powder pink or ice blue let more light through, so pay more attention to opacity in those shades.

When choosing, ask yourself: will this piece sit against the skin or be worn on top? In a set made for summer nights, like the Camisole + Shorts, what you are looking for is lightness and coolness. In a long, belted piece like the Lace Robe, what matters is how the fabric falls from the shoulder. For sets, see the Pyjama Sets collection.

Is higher momme always better?

No. Momme only tells you the weight. It doesn't tell you two important things:

• The weave: a 19 momme charmeuse is glossy and slippery; a 19 momme crêpe de chine is matte with a fine grain. Same weight, two different fabrics. For weaves, see types of silk fabric.
• Yarn and workmanship: a fabric tightly woven from even, long filament is smoother and more durable than a loosely woven fabric of the same momme.

Also, very high momme doesn't suit every piece. In a summer nightdress with thin straps, overly heavy fabric drags the straps down and becomes an unnecessary layer on a warm night. The right momme depends on what the piece is and when it will be worn. Look for the one that suits the piece, not the heaviest.

Momme by weave

Each weave works best within a certain weight range. Sheer fabrics such as chiffon and organza sit at low momme; they are woven to be fine and light in the first place. Habotai is mostly light to medium weight. Charmeuse and crêpe de chine are made across a wide range, and most of the weights used in sleepwear are in these two weaves. In fabrics with body, such as twill and dupioni, the weight adds to the crispness of the cloth itself. When comparing products, always read the momme together with the name of the weave: 19 momme charmeuse and 19 momme habotai are not the same fabric.

Is momme used only for silk?

Momme is used almost exclusively for silk. Cotton, linen and synthetics are measured in grams per square metre. If you see a momme figure on a polyester satin product, be careful: the unit may be misused, or the product may be trying to pass as silk. Check the label first to see whether it is silk. If the label isn't enough, see the tests in how to tell if silk is real.

Does momme change the care?

The basic rules are the same at every weight: low temperature, gentle detergent, no rubbing, drying in the shade. But weight affects care a little. Low-momme silk is more delicate when wet and creases more easily, so handle it more gently when washing. High-momme silk holds more water, so pressing the water out in a towel and drying it flat keeps its shape. Whatever the weight, the label comes first.