Does Merino Wool Shrink? (Complete Guide)

Merino wool is widely regarded to be a quality fabric. It looks and feels premium, and also fits like a glove. But what about its longevity? Does merino wool shrink?

Some merino wool sweaters do shrink if thrown in the dryer or the washing machine. However, pre-shrunk merino wool sweaters can be washed in cold water without any noticeable shrinkage. Merino wool shrinks in the dryer, so such sweaters should always be laid flat to dry.

Now, to get to these results and to find out the exact amount of shrinkage, I decided to do a bunch of experiments. I took three sweaters that have served me well over the course of time, and I ran a bunch of tests on them.

Here’s how it all turned out.

Does Merino Wool Shrink In The Wash?

merino wool

Yes, some merino wool sweaters and garments do shrink after washing. Washing thicker sweaters is more dangerous, while thin to medium pre-shrunk sweaters can be washed if the label says so.

To put this conventional wisdom to test, I decided to do some research.

I took three different merino wool sweaters I own which are made by popular brands such as Uniqlo, Icebreaker, and Howies. These three sweaters have been in my arsenal for over 2-4 years now.

Since I had torn the care label on these garments as soon as I bought them, I didn’t really know how the sweaters were going to look like after the wash. I washed them in cold water with minimal detergent.

I took their measurements before washing as well as after washing.

Comparing these two numbers gave me the “Change in Size” metric. This metric helped me ascertain if my merino wool garments had shrunk or stretched or remained the same in size.

Here are the results of this little experiment, tabulated for your convenience.

SweaterChange in Size
Uniqlo Merino Wool SweaterNo change in size
Icebreaker Merino Wool SweaterNo change in size
Howies Merino Wool SweaterSlightly shrunk
Results of washing merino wool

Now, to get further proof, I contacted all these three companies and asked them about how to take care of their merino wool clothing. Uniqlo and Icebreaker said that their sweaters can be washed with a mild detergent, while the support at Howies asked me to dry clean.

The results of the experiment are very clear.

Merino wool can shrink after being machine-washed, but sometimes no change in size is going to take place. The best thing to do would be to follow the instructions on the care label. If you don’t have access to a care label, it’s better not to wash merino wool and go for dry cleaning instead.

It’s better to be safe than sorry.

Does Merino Wool Shrink In The Dryer?

To answer this question, I put my three merino wool sweaters into the dryer after washing.

I took their current measurements and then compared them with the measurements I recorded after drying them, and tabulated the results.

Like in the previous experiment, this helped me determine if there had been any change in the size of the sweater and gave me the “Change in Size” metric.

This metric helped me decide if my sweaters had shrunk or not.

SweaterChange in Size
Uniqlo Merino Wool Sweater2 inches tighter
Icebreaker Merino Wool SweaterNo change
Howies Merino Wool Sweater4-5 inches tighter
Change in merino wool sweater size after tumble-drying.

As you can clearly see in the table, two of my merino wool sweaters shrunk by a significant amount after being put in the dryer. The Icebreaker merino wool sweater did not have any change in its size, but even they advise against tumble drying.

Through this experiment, I’ve come to a pretty thorough and well-researched conclusion.

Merino wool should never be put in the dryer. This will lead to shrinkage. Even hang-drying is not a great idea here, as that may also lead to a change in size. The best way to dry merino wool sweaters is to simply lay them flat and let evaporation do its work.

How to shrink merino wool?

Shrinking a garment made of merino wool can be done by following these steps:

  1. Fill a basin or sink with lukewarm water and add a mild detergent. Avoid using hot water or harsh detergents, as they can damage the wool fibers.
  2. Submerge the garment in the water and gently agitate it. Don’t wring or twist the wool, as this can stretch and damage the fibers.
  3. Rinse the garment thoroughly in lukewarm water to remove all traces of detergent.
  4. Press the garment gently to remove excess water, then lay it flat on a towel to dry. Avoid hanging the garment to dry, as the weight of the wet wool can stretch and distort the shape of the garment.
  5. Once the garment is dry, you can further shrink it by gently steaming it or ironing it on a low setting with a damp cloth between the iron and the wool.
  6. Be aware that some merino wool garments have been treated to prevent shrinkage, so you might check for tag for care instruction before starting the process.

Note that shrinking wool may change the fit and look of your garment, it’s important to test a small inconspicuous area before treating the entire garment, and to proceed with caution.

Does Smartwool Shrink?

SmartWool is a brand of clothing and accessories made from merino wool, which is a type of wool that is known for its softness and resistance to shrinking.

However, like any type of wool, SmartWool products can shrink if they are not properly cared for.

To minimize shrinkage, it is recommended to machine wash SmartWool products in warm water (not hot) and to avoid using fabric softeners or bleach.

Additionally, it’s best to lay flat to dry or tumble dry low heat, and avoid wring or ironing it. It’s always a good idea to check the care instructions on the product, or on the SmartWool website before cleaning it.

Does Washable Merino Wool Shrink?

There are many merino wool sweaters that are marked as “Washable”. You can machine wash these garments on the cold setting in order to avoid shrinking the clothes.

Sometimes, to avoid giving the customer the hassle of dry cleaning merino wool every time, companies subject their products to something called “pre-shrinking” or “pre-washing”. It is a chemical process that ensures that the merino wool does not shrink at all.

Some (though not all) pre-shrunk wool sweaters can also be tumble-dried. This information is generally provided on the care label.

Another way to avoid merino wool from shrinking, which manufacturers often do, is blending it with other fabrics. This process takes the best of both worlds.

For example, merino wool is often presented in a blend with polyester. This gives the wool blend sweater the anti-shrinking properties of polyester along with the warmth of high-quality merino wool.

Read: Does Merino Wool Stretch Out Over Time? (Know This Before You Shop!)

Frequently Asked Questions

Does Shetland Wool Shrink?

Shetland wool will shrink in a very minor way if it is washed in cold water. You should never put Shetland wool in the dryer, as that would lead to major shrinkage and reduction in size.

Do Icebreaker Sweaters Shrink?

Icebreaker sweaters do not shrink in the wash. However, drying them might lead to massive shrinkage if they are made from pure merino wool. Merino wool blends from Icebreaker are generally okay to wash.

Final Remarks

Merino wool is a fabric that has a lot of pros and cons. It’s warm, but it is also expensive. It’s durable, but it is also prone to shrinking.

Yet I always recommend people to have some quality merino wool items in their closet. Focus on the word “quality” here. Buying quality pieces leads to a sustainable future where you look amazing and receive tons of compliments.

Another way to keep your fashion needs met (while being in the sustainability framework) is dyeing your clothes so that they look brand new (rather than buying something brand new).

If you want to know how you can dye your merino wool garments, check out this guide.