Our Sock Weights: A Complete-ish Guide

Ultralight, lightweight, midweight, & heavyweight Merino Wool strands

Professional governing bodies recognize a total of 17 weight classes in boxing. Professional governing bodies recognize a total of 4 weight classes in Darn Tough socks.

Choose Your Fighter:

When we talk weights, we are referring to the specific yarn in the sock and the relative thickness of that yarn. We're not talking about how much the sock weighs on a scale. Yarn comes in weights, and while measured in microns (a very small measurement, one millionth of a meter to be exact), it can make a difference. The finer the yarn, the smaller it is in diameter.

When you think of yarn, you’re probably thinking of the yarn balls your grandma used when she knit you that itchy sweater (or otherwise bulky wool garment) when you were a kid. The Merino Wool we use isn’t that thick, and most certainly not that itchy.

In this Merino Wool weight guide, you’ve got 4 general categories:

  1. Ultra-lightweight
  2. Lightweight
  3. Midweight
  4. Heavyweight.

At Darn Tough we only use Merino Wool, Nylon and Lycra in our socks. Merino Wool is the main material, but using it alone would not allow the sock to keep its shape, so you need the other materials to help with that. Part of the reason why working with different yarn weights helps.

Infographic showing how Merino Wool, Nylon, and Lycra Spandex help make our socks so good

Why Sock Weight Matters:

The type of cushion and insulation you need in a sock will change depending on what activity you are using it for. The fabric weight helps to describe the amount of warmth a sock may have, and it also means more Merino Wool, so you enjoy more of Merino’s natural benefits.

For instance, our Heavyweight sock will use the heaviest yarn because it will keep you the warmest. Think about it like bulking and shredding season. The colder the weather becomes, the more bulk you want to put on in to keep you warmer. That’s when you’ll find yourself grabbing a pair of heavyweight socks.

Versus warmer weather months, where you’ll want to shred that excess weight you’ve put on because you now want to keep cool. That’s when you’ll transition your sock drawer and opt for more of a Lightweight or Ultra-Lightweight option. Like a boxer weighing for their fight. Like a hiker choosing a lighter base layer. 

Infographic showing Darn Tough sock weight/thickness options from ultralight to heavyweight

Ultra-lightweight Socks

The absolute lowest profile that is nearly a second skin. Weighing in at around 16.5 microns (human hair is about 100!), even with cushion, these ultralight socks are sleek and silky smooth.

The fineness of the yarn is great for activities like running or skiing, where you want something lightweight, because the permeability helps regulate your foot’s temperature and keep your feet dry.

Lightweight Socks

Person with bicycle wearing lightweight socks with a vegetable pattern

Moving up a weight class to the arguably most versatile weight of socks. Lightweight socks can be found in practically every one of our sock categories from hiking to athletic to lifestyle. Pair it with cushion and you’ve got a Championship Belt.

Midweight Socks

While Lightweight may be versatile, Midweight socks will hook ya’. In just a single wear this will take you down – in a good way.

Closeup of feet in hiking boot wearing midweight socks with a rocket ship outhouse design

This is where our hiking socks and ski socks made their name and with some of our bestsellers in this category (hello Hiker Micro Crew) they’ve taken out their competition in one go. With more natural insulation, and so durable they are a thru-hiker staple.

Heavyweight Socks

Our warmest socks, for truly cold weather. Unlike our other socks weights that can come with or without cushion, our heavyweight socks always come with cushion, if not a full cushion of terry loops.

Man seated on couch with feet up wearing heavyweight socks

A higher yarn weight means more Merino, so you can probably gather that these socks usually have the highest Merino Wool content of any styles, allowing for maximum Merino Wool benefits.

Don’t worry, while it is the thickest we knit with, it is still thin, like a thread – still much thinner than grandma’s sweaters.

Mix n’ Match

While there are 4 major weight categories, when you add in our multiple sock heights and cushion preference, you unearth many combinations that can compete in different weight classes to become a multiple champion.

Take for example our Micro Crew height. You can find this height in an Ultra-Lightweight option in our thin running socks, like the Bolt, or in a Midweight option in our Hunt line, like the Hunting Boot sock.

Material Gains

We should mention once again that our socks are knit with Merino Wool, a naturally thermoregulating material. Which means that no matter the season, no matter if the weather is hot or freezing, our wool socks will help to warm you up or keep you cool.

You don’t need to completely go sock-free to feel your coolest in the summer, and you don’t need to layer 2 pairs of socks in the winter to keep warm. Choosing the right weight and adjusting to your preferences will keep you comfortable in any activity… in or out of the ring.

Person climbing tree wearing lightweight socks from darn tough

No matter what the class, our socks always come out on top. And if you’re putting Merino in the ring with cotton… that’s a TKO.

Sock choice is personal. You can mix and match height and weight to your personal preference, to find your perfect type of socks. Our Sock Finder quiz can give you a hand with that. 

Download Darn Tough's quick reference guide to the different types of socks here.