Do Merino Wool Socks Shrink in The Washer and Dryer?


Washing and drying wool clothing can be tricky at times. Throughout the years, I’ve shrunk more merino wool base layers than I care to admit. It doesn’t take long for a careless mistake to ruin your wool clothing.

Looking back I can’t remember ever shrinking a pair of merino wool socks. So I decided to reach out to a few of the biggest Merino Wool Sock companies to see if their products shrink in the dryer.

So do merino wool socks shrink in the dryer? Some brands of merino wool socks will shrink, but most have been treated to withstand machine washing. Companies like Smartwool and Darn Tough preshrink their socks, but it’s still a good idea to wash in cold water and let them air dry.

Whether or not your merino wool socks will shrink depends on the brand and how your socks were made. In this article, I will explain how to figure out if your socks will shrink in the wash.

My Favorite Merino Wool Sock Brands (These Won’t Shrink)

  • Darn Tough Hiking Socks (Longest Lasting): Darn Tough socks are by far the best merino wool socks on the market. They are by far the most durable wool socks on the market, but boy are they expensive.
  • Smartwool Socks (Most Comfortable): Smartwool socks might not be as durable as Darn Tough socks, but they’re way more comfortable. At a fraction of the price of Darn Tough socks these are the perfect balance of price/durability.
  • People Socks (Budget Option): People socks are warm and comfortable for around the house, but they won’t handle heavy use. They’re not bad for the price, but they won’t make it through your average workweek or camping trip.

Do Merino Wool Socks Shrink?

Think about what company made your socks. If they were purchased from a name brand company like Smartwool, Darn Tough, People Socks, etc, you shouldn’t have anything to worry about. Most major manufacturers preshrink their socks and treat them so that they can be machine washed.

Problems could start to arise when washing socks of unknown origin. It all depends on how the socks were treated and the quality of wool used. High-quality socks with premium wool should not significantly shrink in the wash.

I need to clarify that I’m not talking about slight shrinkage. After your socks stretch from normal wear they will most likely shrink down to normal size in the wash.

It’s kind of like how jeans always feel tight after coming out of the dryer. They feel tight for a bit then they stretch back to normal. So they don’t really shrink, they just reset back to their original size. It just gets rid of all that bagginess that develops with wool after regular use.

I highly recommend separating your wool socks and running them on a gentle cycle with cold or warm water. Try to avoid using hot water, because it might shrink wool. After the socks are clean, either tumble dry on a low setting or lay them out flat to dry.

What Did Smartwool Have to Say?

Here’s what the customer service department at Smartwool had to say when I asked if merino wool socks shrink.

“As long as the proper washing and care instructions are followed the product should not shrink. We recommend you wash your products in cold or warm water on a gentle cycle and air dry for the best appearance or tumble dry on low heat. We suggest to turn your items inside out when washing. Do not bleach, or iron and do not use fabric softener or dryer sheets.”

Smartwool Customer Service Department

So according to Smartwool, your socks shouldn’t shrink if you follow the safe washing directions. They recommend only using cool/warm water and the low heat dryer setting.

This leads me to believe that it’s generally safe to wash/dry merino wool socks, but heat could potentially shrink the product.

What Makes Merino Wool Shrink?

I’ve often wondered why some wool garments shrink and others don’t. After a little bit of research, I finally figured out the cause. It all boils down to how the clothes were treated and what they’re made out of.

Most merino gear is treated to withstand a washing machine. They don’t even need to use anything to preshrink the wool. All it takes is a little bit of hot water and artificial heat.

After they go through that preheating cycle they should be able to withstand a typical laundry cycle. It’s still a good idea to avoid heat, but not entirely necessary.

So what causes wool to shrink? Moisture, heat and a little bit of agitation will shrink wool. The rough untreated wool fibers hook onto each other and tighten up. It’s kind of like how your hair gets frizzy on humid days.

Can Marino Wool Socks Go In The Washer and Dryer?

You can really go a long time between washing wool socks. Merino wool has anti-microbial properties so you don’t need to wash the socks after each use. They won’t smell and the bacteria can’t reproduce. So you shouldn’t have to throw your socks in the wash as often.

For the most part, yes merino wool socks can go in the washer and dryer. Just make sure you check the manufacturer’s care label. Some products just weren’t designed to go in a washer and dryer. I get into figuring out if socks can go in the wash in the section below.

How To Wash Merino Wool Socks

  1. Turn Socks Inside Out

    Turn your merino wool socks inside out to prevent damage.

  2. Machine Wash

    Set the washing machine to the gentle cycle and machine wash in warm or cool water. Hot water can shrink wool so avoid the hot water cycle.

  3. Use Mild Soap Without Bleach

    Choose a mild soap that doesn’t contain bleach and fabric softeners. You can use regular old laundry detergent, but I prefer detergents made specifically for wool. I prefer the feel of Nikwax Wool Wash over Woolite, but it’s hard to find in stores and expensive. Laundry detergents made for wool clothing makes your socks feel so much softer than regular detergents.

  4. Tumble Dry or Air Dry

    You can tumble dry your socks on a low heat setting, but most people just let their socks air dry. I just take mine out of the washing machine and set them on top of the washer. Come back in a few hours and they’re perfectly dry ready to be put away. Be careful hanging wet wool! It can stretch out the wool and distort the shape of your socks.

How-to: Will My Merino Wool Socks Shrink?

Here’s a 4 step approach to figure out whether or not your merino wool socks will shrink in the wash.

What Brand are They?

Try to figure out the brand name of your socks. Clothing manufacturers know how annoying it can be to have clothes shrink in the washing machine.

Almost every major brand preshrinks their socks so you won’t run into problems. Just be careful when purchasing your socks. I usually stick to Darn Tough socks for work/hiking and Smartwool for general all-purpose use.

You get what you pay for with merino wool. Don’t even bother with cheap generic house brand socks. They rarely last for more than a day or two before getting holes.

How Old Are The Socks?

If you’ve purchased the socks in the past couple of years they should be fine. Modern wool socks use specialty “Superwash Wool” designed to withstand normal wash cycles.

They just use high-quality wool with fine fibers, instead of the loose fibers found on older socks. So they don’t bind up and contract in the wash.

Check The Washing Instructions

The easiest way to check whether or not your socks will shrink is to check the wash instructions. If there are no special wash/dry instructions then you should be good to go.

Unfortunately, you probably threw away the washing instructions the minute you put on your socks. If that’s the case check on Amazon to see what people said in the reviews. Check the search box at the bottom of the page where people ask questions about the product.

How Do Your Merino Wool Socks Feel?

Do your socks feel scratchy or are they smooth to the touch? If the wool feels smooth and soft to the touch it’s most likely Superwash wool. This means that it should not shrink in the wash.

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