Satin vs silk: what’s the difference?

Satin isn’t a material, it’s a way of weaving. Silk is a fibre. So a satin can be silk, acetate, viscose, cotton or polyester, and it’s the label, not the sheen, that tells you which one you’re holding. Silk satin is both at once.

The question usually starts with a pillowcase or a sleep bonnet sold as “satin”, next to a much dearer one sold as “silk”. On those labels, plain “satin” nearly always means polyester. If it were silk, the maker would say so in large letters. On our shelves, the same word covers fabrics from €5.99 to €69.99 a metre.

Satin: a way of crossing threads

Every woven fabric is made of two sets of threads, the warp, running the length of the cloth, and the weft, which crosses it. In a plain weave they alternate over, under, like a chequerboard. In a satin, each warp thread passes over at least four weft threads before going under a single one, and those binding points are staggered so that they never touch or line up into a diagonal. That is what sets it apart from twill.

Those long runs, called floats, make a surface with almost no texture, and that surface is what reflects the light. Turn the fabric over and you’ll see the other set of threads, matt. So the sheen comes from the weave. A long, smooth fibre makes the most of it, and silk is one, but so is polyester.

The word itself does come from silk, though. It probably goes back to Zaitun, the name Arab merchants gave the Chinese port of Quanzhou, where the silks they called zaytūnī set sail from.

Six satins, one weave

Here are six from our October 2026 stock, with the weight and price shown on their product pages. Our weights are given per linear metre (g/ml) and converted here to g/m², so that different widths can be compared.

Look at the three duchess satins. Per square metre, the silk one and the polyester one weigh the same, 160 grams give or take a gram, and the first costs nearly six times as much as the second. The acetate one, heavier than both, is still almost three times cheaper than the silk.

Weight, name and sheen tell you nothing about the fibre.

The difference is in the hand and in the wearing. Silk satin flows, follows the body without clinging and catches the light in soft glints. It breathes, too. Silk can take up about 11% of its weight in moisture, polyester less than 1%, which is why a synthetic satin turns clammy on a warm evening. In return, polyester is tough and cheap, while silk loses up to a fifth of its strength when wet.

At the machine, none of them does you any favours. They all slip, and on every one a pin leaves its hole. A length of satin left on the edge of the cutting table ends up on the floor the moment your back is turned, whatever the fibre!

For a bias-cut evening dress, we choose silk without a second thought. For a bridesmaid’s dress that has to hold its shape all day without breaking the bank, acetate duchess satin is an honest choice, and its weight gives it body. Cotton satin, often sold as sateen in English, is an everyday fabric, and its touch of elastane makes fitted trousers or a pencil skirt that go in the machine.

How to tell silk from polyester satin

Start with the label, the only sure test and one that damages nothing. In the EU, Regulation 1007/2011 reserves the word “silk” for the fibre of silkworms and allows only fibre names in a composition, which “satin” is not. Only a fabric made of a single fibre may be labelled “100%”; a blend is listed fibre by fibre, like our wool and silk satin, at 62% wool and 38% silk. A fabric’s name is no substitute for that line: “silk satin” in a title doesn’t tell you how much silk is in it.

Price does a first sort. Our plain silk satins start at €35.99 a metre, and a plain satin sold for a few euros is not silk, whatever it’s called.

Eye and hand get it wrong more often than you’d think. Silk owes its soft sheen to a fibre with an almost triangular cross-section, which reflects light at several angles; polyester makers spin trilobal fibres precisely to imitate it. And static, often held up as the giveaway of a synthetic, doesn’t spare silk in dry weather.

That leaves the burn test, on a single thread. It tells fibre families apart, not one silk quality from another.

The test has its blind spots. Wool smells exactly like silk, a finish can muddle the result, and a blend sends mixed signals. A thread that melts, then a whiff of burnt hair, and you’re left with more questions than you started with.

Nathalie’s tip: take the thread from an offcut or a seam allowance, never from an edge that will show, and hold it with tweezers over a plate, with a glass of water to hand. Then burn a warp thread and a weft thread, because a fabric can perfectly well have its warp in one fibre and its weft in another.

Satin or silk for sleep and hair?

For a pillowcase or a bonnet, smoothness matters most, and polyester satin is smooth too. Silk adds what it does best, taking up moisture instead of leaving it against your skin. Silk pillowcases are mostly sold at 19 or 22 momme; our plain silk satins run from about 17 to 22, and our washed silk satin, softened by a wash during manufacture, is 22, with a more matt hand.

One caveat, though. A pillowcase gets washed far more often than a garment. If you want a washable pillowcase, first wash an offcut by hand in cold water and let it dry flat. You’ll find out whether the colour holds and whether the satin marks.

Frequently asked questions

Is satin a natural fabric?

It depends on the fibre. Silk or cotton satin is natural, viscose or acetate satin is regenerated from wood or cotton cellulose, and polyester satin is synthetic.

Silk satin, charmeuse, duchess satin: what’s the difference?

All three are satins. Charmeuse is a light, fluid satin with a matt back, the kind used for bias-cut dresses. Duchess satin is its opposite, heavy, dense and firm, the satin of wedding dresses that hold their volume.

Next time a label says “satin”, ask it the only question that matters: satin made of what? The answer is on the composition line, and nowhere else.

Happy sewing,
Nathalie