How to Unshrink a Sweater (and When You Can't)

Some mildly shrunken sweaters can regain some size with gentle reshaping. Shrinking tightens the knit and is usually reversible; felting locks the fibers together permanently and isn’t. The two look similar at first glance, but they behave very differently.

Shrinking tightens the knit while keeping the stitches visible. Felting makes the surface dense and fuzzy, and the stitches disappear.

Take a close look at the sweater. If you can still see the individual knit stitches — the loops and rows that make up the fabric — the sweater has shrunk, and the fibers are still intact. Most of the size can usually be recovered.

If the surface has gone dense and matted, and the stitches have vanished into something closer to fabric than knit, the sweater has felted. That happens when heat, moisture, and agitation cause the microscopic scales on wool fibers to interlock permanently. There’s no reversing felting. A felted sweater can sometimes be repurposed, but it won’t come back to its original size or feel.

Soak for about 30 minutes in cool water with a capful of wool-safe conditioner at its recommended dilution and rinse, if necessary. Then gently reshape while damp and dry flat.

• 1.  Fill a basin with cool water — not warm.

• 2.  Add a capful of hair conditioner or a wool-safe conditioner. It coats the fibers and helps them slide back into place.

• 3.  Submerge the sweater and let it soak for about 30 minutes. Don’t agitate.

• 4.  Drain. Press the water out against the side of the basin — don’t wring.

• 5.  Roll the sweater in a towel to absorb more water.

• 6.  Lay it flat on a fresh towel and gently reshape it back toward its original dimensions. Work across the whole garment a little at a time rather than pulling one area.

• 7.  Pin the edges if needed. Gently reshape and dry flat, away from direct heat.

Expect to recover most of what was lost — not always all of it.

Heat, moisture, and agitation can contribute to shrinkage.

Three causes do most of the damage: hot water, tumble drying, and vigorous agitation. A sweater that “shrank” after hanging wet from a hook may have actually stretched first and then contracted unevenly as it dried.

Cold water, wool cycle, no tumble dryer, dry flat.

Follow the garment’s care label as a floor. Machine-wash only if permitted, and dry flat unless the label allows tumble drying. Cold water. Wool or delicate cycle. Low or no spin. The two most common places sweaters get damaged are the tumble dryer and a laundromat that puts everything in on hot. If someone else is doing the laundry, pull sweaters out first and lay them flat yourself.

For the full care procedure, see the wool washing guide.

A felted sweater won’t return to size. It’s dense, warm, and hard-wearing — useful for other things.

Felted wool doesn’t fray, holds heat well, and can be repurposed as a base for cushion covers, mittens, or a lining. That doesn’t undo the loss of the sweater, but it’s a better ending than the bin.

Fiber length plays an important role in how well a sweater survives repeated washing — longer fibers stay anchored in the yarn and hold up through more cycles. Quince Mongolian cashmere runs 34 to 36 millimeters in length, on the longer end of what’s commonly available.