Silk pillowcases: how to choose the right size

Bed linen manufacturers cluster around a small number of dimensions. Here they are, with the use each one is meant for.

These figures describe the pillowcase, not the pillow. A pillow sold as “50 × 70” is a filled envelope: once stuffed, it is thicker than a flat rectangle, and its usable surface differs slightly from its flat dimensions.

This is the most common mistake. A pillowcase washed many times may have stretched or shrunk, and its label no longer says much about its real size.

1. Take the case off and lay the pillow flat on a bed or table.
2. Flatten it gently with your palm, without crushing the filling.
3. Measure the width from seam to seam, across the middle.
4. Measure the length the same way.
5. Note the thickness: hold a ruler vertically against the edge and read the height at the thickest point.

Thickness is the measurement almost nobody takes, and it is often the reason a pillowcase “in the right size” turns out too tight. A firm pillow 15 cm thick uses up several centimetres of width and length that a soft 8 cm pillow does not.

The choice is not only aesthetic.

The rectangular format follows the line of the shoulders. It is the default sleeping format: the head rests in the centre and the edges stay free. On a 140 cm bed, two rectangular pillows sit side by side without overlapping.

The square format takes up more surface and behaves differently. Many sleepers use it as a back pillow against the headboard, with a rectangular one in front. Some sleep on it, particularly people who move a lot during the night: the surface is wider, so you leave it less often.

If you are hesitating and you sleep on your side or your front, the square gives you more margin when your head shifts.

A badly sized pillowcase does not tear on the first night. It behaves badly, and on silk that shows sooner than on cotton.

Too large: the fabric forms folds, and those folds mark your cheek. The smooth effect you were after disappears wherever the fabric moves. The case also slips off more easily during the night.

Too small: the filling pushes against the seams constantly. Silk is a strong fibre in tension but a fine one; a seam under permanent strain wears out faster than the fabric around it. This is the most common failure point on a badly sized silk pillowcase.

Right width, wrong length: the most frequent case, and the most tolerable. The case behaves properly, it is simply more enveloping or a little shorter than expected.

This is the situation that really raises questions, and it deserves its own answer. A gap of one to four centimetres between pillow and case does not have the same effect on the width as on the length, and it depends on how firm the filling is.

We have worked through the most common case in France — a 50 × 70 pillow and a 48 × 74 case — in a dedicated article: is a 48 × 74 cm pillowcase compatible with a 50 × 70 cm pillow? The checking method it describes works for any difference in dimensions.

Our pillowcase comes in two sizes, both in 22 momme mulberry silk and available in all ten colours:

• 48 × 74 cm — the rectangular format, a little longer and a little narrower than 50 × 70.
• 60 × 60 cm — the square format.

Size is chosen on the product page, independently of colour. If you are still hesitating after measuring, the rectangular format remains the safer choice for ordinary sleeping use.

Can you put a square pillowcase on a rectangular pillow?

Technically yes, but the result is poor: the pillow swims inside the case, the excess fabric falls to one side and creases. The reverse — a square pillow in a rectangular case — does not work at all.

Should you size up for a thick pillow?

Not automatically. Measure the thickness first. Below roughly 12 cm, a case matching the pillow's dimensions is fine. Above that, and if your pillow is firm, the extra margin becomes useful.

Does a silk pillowcase shrink and change size?

Washed properly — at 30 °C, in a laundry bag, never tumble dried — a mulberry silk pillowcase keeps its dimensions. Changes almost always come from a wash that was too hot or a spell in the dryer. The details are in our article on washing a silk pillowcase.

How can you tell whether a pillowcase will fit before buying it?

Measure your pillow flat, compare both dimensions, and check the thickness. If the gap is under two centimetres on each side and the pillow is not especially firm, the case will fit.

And if I choose the wrong size?

You have fourteen days from delivery to withdraw, with no reason required. The terms are in our refund policy.

Size is only one of the criteria that separate two silk pillowcases. The others — weight, type of silk, closure, care — are gathered in our guide to choosing a silk pillowcase.